Over at Fullscreenmario.com, there’s a full beta build of the original Mario Brothers that you can play on your PC and Mac right now (providing your using Chrome as your browser). The controls may be a bit odd as using the space bar and the arrow keys still doesn’t feel as comfortable as an NES controller in your hand, but it’s amazing how fun of a game it is all these years later.
Oh what’s that? Still not impressed? FullScreenMario.com also features a full level editor. You can create your own levels from scratch or you can modify the existing levels. You didn’t want to work today did you?