Let's see. For starters, there's Harenchi☆Punch - now 80PAN! - a 3-strong girl band comprising a two vocalists (one of whom plays the guitar) and a rapper. I have only a few reasons for liking them, but none for disliking them...
1. Their vocalist has an awesome voice - she's not squeaky like Otsuka Ai, and she's not too husky like Onitsuka Chihiro. Her voice is... just nice. Go Tomomi!
2. Their songs are immensely fun, and though their PVs are kind of stupid, they really get you.. bouncing? Moving, at the very least.
So yeah. Harenchi☆Punch is great, if you like that sort of thing. They're kinda like HeartsGrow, but minus the guys.