Although what this promotes is probably not something the majority of the community wants, I'm simply spreading the word.

Valve recently fixed a bug that made custom sounds not work, and now they do! So what are these custom sounds? They work identically to sprays, except apart from spraying a decal, you play a sound. They are disabled by default, but if you do want to hear them, type CL_customsounds 1 into the console.

To make your own you need to make a sound file that is 44100Hz Sample Rate, Mono Channel, is a .WAV and under 512 KB in size. Rename it to jingle.wav, and place that in: C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\custom\my_custom_stuff\sound\player

Then you need to tell TF2 where to find the sound. Type cl_soundfile sound/player/jingle.wav into the console.

Then you need to bind it to a key in-game, the command is "impulse 202". So i.e. to bind H to play your sound, type bind H "impulse 202" into the console.

Oh cool, thanks for the info. I'll have to make a "Lots down push" sound