I've played the High School Musical ones before (yes, I'm a dork). I haven't done any singing games in a really long time, but I remember the Karaoke Revolution: American Idol games are also good (and I'm not even a fan of the show).
Funny singing games... i don't own any but I fool around with my friends when I go visit them. It's so silly when I start to sing because I have literally no voice whatsoever. I'm surprised the neighbours don't call the cops on us, we must sound so awful singing those tunes.