Sentinels of Echo City!
Oh... what a joy....... OSR = Omnifarious Superheroic Ruleset!
I'm writing this review for the SECOND time now because RPGNow decided to purge all but the first line of my last one.....
If TSR's B/X D&D procreated with their Marvel Super Heroes game, you'd get the first genetic version of SoEC... after that though you'd need to inject it with mutagen, expose it to gamma radiation, let it be bitten by a lab arachnid and then sprinkle it with cosmic dust.
This game is a ton of fun. The rules are lightweight and fast yet robust enough to adjudicate any situation that comes up. The game uses a unique "Trait" system that covers both Powers and Skills under one cleverly erected umbrella. It should be noted too that even though you can run full fledged four color supers, the rules also have everything you need to run low powered or even pulp type games.
The setting fluff is purposefully barebones and though there is plenty of stuff to branch off from, it takes a decidedly DIY approach to setting. Inside you'll find tons of npc's, adventure hooks and personalities but they are there to help you launch your own "Echo City".
The author has already released quite a few supplements for the game (including one that is a best seller right now!), and there's a robust G+ Community that is creating stuff too:
[5 of 5 Stars!]