Avengers Arena and Avengers Undercover by Dennis Hopeless:
I don't think I've ever read anything from Hopeless before, but these two series made me want to seek out more of his stuff (oh hey he wrote Spider-man...Greg Land on art...riddled with tie ins...nevermind).
Arena is an obvious cash in on the Hunger games craze that was going on at the time, but it's well written, I cared about the characters (more than I did in Avengers academy with those set of heroes, but I really should go back and give that series another read) the art is mostly good, especially Kev Walker, and Hopeless is not afraid to shake things up a bit.
Also they explain why it's a Hunger games/Battle Royale rip off. But even if they didn't I think that concept is strong enough to work with teenage superheroes (especially with the added drama of them being basically sworn to be the good guys and then slowly watch them turn against each other).
Undercover is a good sequel, maybe not as good as Arena but it's still engaging and I would like to see this group of kids forming a team and having some further development (make them the new Runaways maybe, although that ship has probably sailed by now).