The Drowsy Chaperone is a fantastic throwback to 20's musicals and a great metamusical at that. Definitely seek out the cast album. I also really like 25th Annual Putnam County Spelling Bee, but there are things the cast recording doesn't have, like the audience participation, you might want to go look at videos of the show on Youtube, like high school performances, to get an idea.
If you like South Park, The Book of Mormon is an easy recommend. Chicago is a great one too. If you like Wicked, go check out Pippin, same composer and lyricist. Closing out my recommendation I'll leave with Urinetown. Yes, it's an awful title.