I think it was MTV and there was some band (I wanna say it was some one hit wonder) and they had fans try to answer questions about them and if they got it wrong they got pied. Does this ring a bell for anyone else?

Vaguely recalling something with O-Town... I'll check the archives

I believe the show was TRL and the group in question was named Cobra Starship. Their video for "the city is at war" features people hitting each other with pies.