I love gaming amalgamations. Combining all kinds of fun flavors to make new and exciting things is simply fascinating. Take this mash-up of Fallout 3 and Halo 3, for example, where someone added the V.A.T.S. combat system to the beloved Bungie shooter. Awesomeness ensues.
[youtube]http://www.youtube.com/watch?v=r4_PUMHtKV8[/youtube]