The single best thing 50cent has done is his second video game, "50cent: Blood on the Sand". It's legit (unintentionally) hilarious and still, somehow, really playable and fun to play, with great co-op. I'm not a fan of his music at all, and the game is a total blast.
He gets a free pass with me just for that game alone, I'm totally okay with seeing what he'd do in a Predator movie.