There has been a slew of crazy and creative mods for the original Doom over the years, offering players a variety of different themes, from pirates to Donkey Kong. One recent mod from user demo_the_doomer has converted the game into a re-imagining of the classic N64 title, Goldeneye 007. It's pretty cool, but strange to see two genre-defining shooters combined into one game.
The mod is still in its early stages, and it's not intended to recreate the game in the Doom engine but to re-imagine what Goldeneye would be like at the same speed as Doom. You can try out the demo for the mod over on its Moddb page.