tl;dr Buy an Edgerouter ER-X and configure it using these instructions

The problem: lag and ping spikes

We're probably all familiar with the terrible lag you can get when your home internet connection is congested. It could be a house mate downloading with bittorrent, netflix, steam, automated device updates....
It doesn't have to be this way, and in this post I'll explain what you can do by fixing a thing called "bufferbloat".

Measuring bufferbloat

First of all, you'll want to get a quick idea of how bad your ping gets when your connection is congested. To get a rough idea, run the DSLReports speedtest. Please use an ethernet cable, if you're on wifi or a powerline adapter, you're gonna have a bad time.
The bufferbloat score is directly related to your lag during congestion. Anything worse than A+ or A means you'll lag badly if your connection is congested.
Regardless of how fast your connection is you can suffer from bufferbloat. I've seen fiber 500/500Mbit connections with over 500ms of bufferbloat.

Bufferbloat is the enemy, and using the tips below, I took my bufferbloat score from a C to an A+.

How to fix it

There are basically two ways to get these improvements, the first one easy and the second one a little harder, but they both involve traffic shaping and QoS.
1. Buy a $50 Edgemax ER-X router.
2. Flash a router to OpenWRT/LEDE (could be your current one, but you might lose WiFI depending on the chip used in the router)

So first of all, buying an ER-X router:
It's cheap, it's great and it comes with some tools baked in to fight bufferbloat. Battle(non)sense made a great video about how to configure a router like this. In the video he uses the slightly more expensive ER-L, but for our use case the ER-X is both cheaper and faster. The instructions are the same.
Once you've done this, you'll have the 2nd best method of fighting bufferbloat. For bonus points you can go over to the Edgemax forums and get your hands dirty to install the best method of fighting bufferbloat, it's called "cake", because it's a piece of cake to configure. Cake also has an extra neat feature where it will fairly divide the available bandwidth between the devices using the connection.

The second option is to flash a router to OpenWRT/LEDE:
This is a custom firmware for your router and it has the bufferbloat fixes included. You might even be able to flash your current router to this firmware, but depending on the wifi chip used in your router, wifi might not work or work worse after flashing, so beware. Flashing instructions vary between models, but for quite a few routers you can just load the custom firmware in the current web interface of your router, easy!

Limitations

1. Traffic shaping is reasonably tough on the CPU in a router, depending on your connection speed you might need a beefier router to handle the speed. Here are some rough numbers for what a given router can handle in traffic shaping speed (total speed up+down, so a 200Mbit down, 20Mbit up connection would need 220Mbit/sec)
Edgemax ER-Lite: 70Mbit/sec (170Mbit/sec with some hacks)
Edgemax ER-X: 180Mbit/sec (220Mbit/sec using "cake")
Linksys WRT1200AC: 500Mbit/sec
Linksys WRT1900AC: 700Mbit/sec

2. If your internet speed varies due to a crappy ISP, you'll need to update the traffic shaping speeds to compensate. My ISP is currently so congested that I can only count on 100Mbit instead of 200Mbit download during some evenings. So I need to change my settings to compensate for this.

3. Your traffic shaping router needs to be the only thing directly connected to the internet. So if you have cable/dsl modem with built-in wifi you need to disable or not use this wifi signal, as it will bypass the traffic shaping. All your traffic must flow through the traffic shaping router. If your cable/dsl modem supports "bridge" mode, use that.

4. To keep the bufferbloat under control, you give up about 5-10% of your internet speed. I get 190Mbit down and 38Mbit up with the fixes enabled vs 200/40 with the fixes disabled. But I gladly make this tradeoff for a much more responsive connection.

P.S.
My connection without any fixes: No prioritization of download, upload and pings, so bittorrent is just as important as gaming traffic. 100+ms higher ping during congestion.
My connection with Cake traffic shaping: Prioritization of traffic depending on the type, 5ms higher ping during congestion.

Download and run WinMTR or Pingplotter. Let it make a trace to 8.8.8.8 while you're playing.

If the ping is already spiking towards the first hop (your router), it's probably just a case of congested wifi. Use a wire.
If the ping starts to spike after the router, your internet line might be congested. Because you're sharing the connection with other people or devices.

1. You're on WiFi
2. You're on a shared connection

You can't fix that with a VPN or other tweaks on your end.

Get a wire and if your college connection is fast enough you'll be alright. If not, tethering a phone on 4G might give a more consistent gaming experience.

Some EU folk @ i39. I'll spare you the picture of Darn literally teabagging Admirable.

https://i.imgur.com/cTD3HFT.jpg

Thank you, but I already have a sparkly scattergun.

Lots of great people on the list, I didn't see Anakin yet, so I'll nominate him.

Take the motherboard out of the case and take out everything except CPU and RAM. Reseat the RAM and CPU. Check the motherboard for things that might cause a short.

Try turning on the PC in this minimal state outside of the case.

Enable net_graph 5 and make a screenshot while it happens.

You can make config files based on the map name, e.g.: cp_badlands.cfg, that config will be executed when that map is loaded.

There are a couple of reasons the sound quality could suck:

1. The headphones are operating using the "headset (HSP)" profile instead of the hifi headphones profile (A2DP). In this mode, audio quality will be that of an old fashioned phone call. This can sometimes be prevented by disabling the bluetooth microphone device of your headphones in windows, if they have one.
   
2. The headphones only support lower bitrate versions of the SBC codec. This will sound like a bad MP3. If your headphones are old, this is probably it.
   
3. The headphones are crap

Bluetooth audio can sound very good if:

1. The headphones support a modern audio codec at a high enough bitrate: high bitrate SBC, AptX, AAC, LDAC. . Anything from a reputable brand made in the last few years will support at least high bitrate SBC (372Kbit max).
   
2. Your system supports these bluetooth codecs. Windows 10 can use SBC and AptX.
   
3. There are a few great bluetooth headphones available and a ton of crap. Some good ones: Bose QC35 (SBC + AAC), Sony 1000x (SBC, AAC, AptX, LDAC) and the Sennheiser Momentum (SBC + AptX).

As far as I know, the batch that I was part of in November 2012 was the last one, so I'm not very surprised many of those people are no longer active.
Apart from those batches, they've more recently given discoverers of critical bugs special items.

Topic is called i61 feedback, so the following is not all specifically meant for Essentials.tf. After doing production for i49, i52, i55 and i58, it was both weird and relaxing not to be involved this time :)

+ HUD
+ In-game framerate (didn't look like 60FPS all the time, but overall smooth and good enough)
+ Warhuryeah, great balance between insightful commentary and taking the piss out of the teams and players if the matches got a little boring or when bad plays were made.
+ Stream encoding quality
+ Splitscreen rollouts and sniper action
+ Quality of casted matches, close games
+ Production quality.
+ Player cams, instantly linked to the in-game observer, very cool.
+ @TF2Essentials twitter and Facebook was alright
+ Comp.tf
+ b4nny giving the LAN just a sprinkle of intercontinental rivalry and lifting SVIFT to 7's level

- Online servers at LAN for the first day again.
- No STVs.
- In-game camera missing too many key moments. Weird considering the experienced observers.
- Audio isssues. Picking up stage music, pitch and speed changes.
- No interviews
- No team reaction shots, no roaming camera, just static shots.
- Little connection to the LAN, just some shots of the crowd in front of the screen.
- Picture-in-picture too small, especially the first day.
- Side-by-side view hurt my eyes sometimes, especially with two snipers zoomed in and looking around.
- Lack of hype leading up to the event
- Lack of written coverage before and during the event
- Intro and outro movie felt underwhelming compared to previous editions
- Teamfortress.tv twitch not auto-hosting Essentials.tf
- Teamfortress.tv in general regarding i61

Overall very impressed by the Essentials.tf production, thanks a lot!

The Picture-in-Picture is for ants

http://www.teamfortress.tv/43116/i61-streamed

It's not about splitting the community, it's about who shows up and actually does the work. There's coverage of i61 because essentials.tf is making it happen.

No client-side device or setting can fix the terrible internet situation you are in. Only by replacing the camp router with a device that does proper QoS and bufferbloat management can you hope to share a connection with 20 people without lagging.

Is tethering your phone an option?