CSS doesn't have the party factor that Halo does. Back when I lived in a dorm we would hook up two tvs and play COD4 and Halo during the majority of the down-time between classes.
"Gotta get the golden AK!!"
That is because most people at "public parties" are not gamers. Regular people want games that are easy with lots of bright colors and flashy lights. CSS does not meat that description...