A nice list of games developers should mix together. The titles suggester are Master Snake Solid (Halo 3 + MGS), Sporeims (Spore + Sims) and more.
From the article: "Formerly direct adversaries, Mario and Sonic teamed up and the result was incredible: high quality games enjoyed by millions of gamers. So it's only fair to believe that mixing various elements from various successful titles would be a great resource of fun (and income for developers) – SoulCalibur went there with the Star Wars characters, puzzle game Lumines Supernova will come to PS3 consoles with a LBP skin and so on and so forth. It's all about mixing the right ingredients and more people will spend their money on your product. But… are there games that will never ever be joined into one single, bigger and better title, even though they really should? Of course there are!"