Like Mega Man? Sure, who doesn't? Like Doom? Used to, at least? Well, how about a combination of the two? That's exactly the idea behind this Mega Man Doom mod.
It's an 8-bit deathmatch, complete with 8-bit textures and sprites. Mega Man's weapons will react exactly as they did in the 2D games, only in a 3D space. The plan is to have all the weapons from the first six games included when it's finally finished. The creator, Cutmanmike, is looking towards completion some time in 2010.
The mod is still in alpha, but you can check it out here. There you'll also find full instructions on installation. The creator reminds that just about everything you see could change before the game is finished. If the current screens are any indication, this could be pretty cool.