In light of the recent passing of Adam Adamowicz, Bethesda decided to release over 1500 pieces of Concept Art from Skyrim, Fallout 3 and Oblivion DLC. This includes over 800 pieces of Fallout 3 CA, ranging from characters to environments, weapons to creatures, and much more. Some of it made it into the game, a lot of it didn't. If you want to check it all out, you can head on over to their flickr stream, and look through them. The sets for Skyrim and Oblivion can also be found right here.
Thanks to No Mutants Allowed