Ok, I couldn't find a definitive list anywhere, so if it's alright with everyone I've began one. This is a list of known homebrews that are either completed or incomplete. In "()" it will whether or not it's available or in circulation. Incomplete refers to games that are in the works or cancelled. No vaporware, that just confuses things and lists could be endless otherwise. This list doesn't include hacks, I'm looking to make a list of games that are made or being made from scratch. It does include ports, however.

Completed:
Bingo (Available in ROM)
BombSweeper for NES (Available in ROM)
Elite (Available in ROM)
Solar Wars (Available in ROM)
Sudoku (Available on Cart)
Tetramino (Available in ROM)

Incomplete:
NeoToxin (Not Yet Available)
Geminim (Not Yet Avilable)
Grand Thefttendo (On Hold? Cancelled?)


Please post any other known titles or corrections to this list!

There are TONS of them.  There is one website from where a guy had a class on them and the site has like 15 playable games that his students made from scractch.  Plus Memblers has made several games as well.  Plus I know bunnyboy is working a few projects as well.  A guy at nesdev is making a nice pitfall game for the NES and has a beta out for it right now.
~~NGD

"games" and "playable" may be a liiiitle over the top to be honest :-)

It's been a while since I've posted here, but there have been a fair amount of new ones developed.

By me:
Geminim (both this and Siamond will be available on a 2 in 1 cart)
Siamond
Mystic Pillars (not yet finished)

By others:
Chunkout 2
Glider
Sarah Parker's Pool Challenge
Super NeSnake
Tic Tac XO

So you will definitely have a lot to play with now.