Generala. The game is more or less complete with a simple rulebook which includes some monsters and a sample adventure, a couple of PC sheets, and a book of pre-gens. There is also a player-only version for printing, which is nice.
The basic mechanic is an interesting dice pool mechanic based on the game of Yahtzee (or more importantly, the games Yahtzee is based off of). I won't go too much into the game in case I feel like reviewing it later, but right off the bat it seems like possible "starter game" for folks that don't know what a d12 is, but want to play anyway.
I don't know about you, but I know some folks that resemble that last remark....
Generala is free, but if you like what you see and get some use out of it you can always buy it again at DriveThruRPG for $2.99. The PDF for sale has an extra 10 pages with what I only have to assume is an expanded Monster section.