Brings me back to when I used to play Skulltag all the time. They threw this song into their engine and if you ran a server you could change the regular Doom music to this with "changemus D_TTFTW" A bit annoying but at the same time, there's nothing like killing zombies and demons to Tiny Tim...
Link
Concupisco
God that song
I cant help but let it loop like 5 times