I just recently discovered rom hacks. While quite a few of them are very good, there is also a lot of junk that I've had to weed through. This is really more to get suggestions than anything. If this has been done a million times, feel free to lock it up (although I couldn't find anything comparable through the search).

So have at it. Think more Crimson Echoes/Return to Dinosaur Land/Outlands and less Dick Tales.

Edit: Just a sidenote; I mean no offense to whoever made Dick Tales. I'm just looking for games that are basically a new game designed off of the original, not just a game with dicks added everywhere.

Check out some reproduction sites, they have good ROM hacks that aren't piles of shit.

Don't go to SMWCentral, it's also filled with tons and TONS of shit.

Lol like naked headless mario?

Stay away from the Little Nemo hack called Little Remo.

parallel worlds remodel is a good one.

1: Roger Rabbit FDS to NES (You guys know where I'm going with this? ;P )
2: pana der hejhog
3: Super Wario World Mini Quest
4: Sonic Megamix
5: Zelda Outlands