It's been said that if Gary Gygax and Dave Arneson still owned TSR around the time D&D 3rd edition came out, this ruleset from Troll Lords would have been it. This is a fun game that brings back that old school RPG fun and feel from D&D and AD&D. Spellcasters have d4 hit die for health, mostly everyone has one attack except for the Fighter, and the Rogue has a long list of skills again. They also have barbarians, bards, paladins, illusionists, knights, ranger, cleric, druid, monk, and Assassin, a special class. Along with a full array of classes, they have an easy Siege system that helps all players learn and play the game without too much number crunching. And to top it off, monsters are scary again and so are the magic items to slay them with.
I'm not sure if this system is considered OSR, but it definitely brings back that nostalgic feeling of playing back in the 80's. Come join even if you don't play and ask questions and discuss this awesome game!