Guybrush Threepwood is in The Force Unleashed 2
This might fall into the 'just because you can, doesn't mean you should,' category of decision making, but Lucasarts have put Monkey Island's Guybrush Threepwood into the Force Unleashed 2 as an alternative skin for Dave Starkiller. Or whatever he's called.
Look at the poor guy, standing in the rain with dual lightsabers in hand. He just looks so sad, as though there's somebody just behind the camera shouting "move your leg a bit, Guybrush, sell it! Make it dynamic! You're not a loveable pirate any more, Guybrush, you're a Jedi! Be the Jedi, and for god's sakes stop crying!"
Of course all will be forgiven with the addition of Star Wars style insult-lightsabre-duelling. "You fight like a Bantha!", "I am rubber, you are hyper-ionised rubber sealant!" Okay, maybe not so good. Either way this has to be one of the weirdest game crossovers out there. What could be weirder, Luigi in Max Payne, perhaps? Or maybe the G-Man as the 10th class in Team Fortress 2?