Super Mario Crossover
I don't know how to adequately express the awesomeness -- and the productivity-killing potential -- of this. It's Super Mario Brothers. But you can play it online. And you can swap Megman, Link, Samus, one of the guys from Contra, and other classic game characters in for Mario. Better yet, the swap isn't just visual: Megaman shoots and slides. Samus rolls and lays mines. If the Senate knew about this game, the filibuster against FinReg wouldn't last 10 minutes: Too many Republicans would vote for cloture just so they could get back to their computers.