Being in a band myself and also seeing a friends band do it, both In The End And Bleed It Out are great party songs. Most people know the words especially ITE. You can throw numb in there too but for just drums and guitar is impossible to pull off unless you Use some sort of backing track.
Haha! Gotcha. That's why I said "Empty Spaces" Because of funniest. Faint is a fun song as is Bleed it Out. Wretches and Kings is fun also. Basically any upbeat song with mike rapping is a pretty fun song, IMO...