For my entry I plan to submit Evil Triad, a card-game prototype made with long-time LD partner @thrainsa & two more friends.
For those who know Final Fantasy VIII, It's heavily inspired by its Triple Triad mini-game. Basically the game rules are the same, but it wraps them in a simple collectible meta-game. It was really fun to make, and it even let us experiment in Unity with multiplayer code (the online mode won't be submitted though, as it's pretty unstable).
At the current state the game is already playable, but I plan to insert a Help screen explaining the rules in-game before submitting the entry.
Also... the game features completely placeholder cards (a mix of previous artwork by graphic artist Prohibe and totally uncleared pics of movie characters)... But replacing them would be a chore at this point so I might release things as it is :P