Have you seen 'Worlds in Peril'
? Its a new superhero rp that is fairly cheap and uses the same system from Apocalypse World, Dungeon World, Monster of the Week, Spirit of 77 and Monsterhearts and a few others.
I wouldn't want to particularly run it, though I know the above games are fun and all use a fairly simple 'roll 2d6: 10+ succeeds, 7-9 is a pass but something happens and 6 or less is a fail but get 1xp for the effort'. At least thats how Dungeon World works and the dice mechanic is pretty standard through the games.
I know you were asking for a group rather than a system, though I figure if people see the mention, a group could be built around it. There's also a free final draft of the rules (wall of text doc style) found here;https://www.dropbox.com/s/knd5b6nc607gyf3/Worlds%20in%20Peril%20-%20Final%20%2810.29%29.pdf
I recommend picking up the actual completed book though.