Jay Pavlina creates a crossover game with the original Super Mario Bros. You can play as different characters such as Simon from Castlevania, Link from Zelda, Megaman, Samus from Metroid, and John Rambo from Contra.
As dorky as the creator is, playing and commenting his own game, I have to say he’s pretty funny and I was enteretained. I’d love to give this a shot. This cross over is as good as it gets. Hat tip: Vinny