Current project is something like a "hands-on" simple sequencer, for kids or just for showing to un-techy people and allowing them to play a little with it. The main idea would be each piece has a given action (loop sound sample, light animation, video mapping, whatever) which will be triggered IF the piece is placed on the board. The idea would be to allow to interchange pieces, with each having a different "effect", and have the output react to the choices.
The placement on the board would also affect the result.
After I have the system working, the idea is to expand that into, possibly, some kind of game board, but that's still a secondary afterthought.
I have to say that electronic-wise I can work at a beginner/intermediate level (I'm more of a programmer), that's why I was trying to keep it as simple as possible with rfid 
Edit: forgot to describe -.-'
The idea would be to keep it simple at first, with around 12 different pieces and a 4x4 board. 5x5 maximum.