You can make a two wire serial protocol to communicate with a microcontroller. You could use a microcontroller simillar to an arduino board as a buffer which gathers information from an accelerometer and send it to the calculator on demand.

Edit: This might work for you as well:
T  G  R
|  |  |
|  |  |
|  |  |
|  |  |
T=tip
G=ground
R=ring

The | lines connected to tip and ring are metal plates. The line | connected to ground is a little rod which can move freely. Mount this to the back of your calc. Every time the wire shorts either tip or ring to ground you can read change in the port state.

Any chance of textures?

Is there an android port of wabbitemu?

There is!

Edit: I could as well just contribute to this discussion. It's cheaper to make a calculator in an FPGA.

Fruit ninja really looks and feels astonishing. It takes a minute to get used to the controls. It's best to use your thumb nail I think. I haven't tried 3d snake yet.

Get rid of the stock ribbon cable and run new wires from the motherboard to the screen module (you will need a soldering iron, solder and some small wires and optional solder braid). Those graphical glitches are mostly caused by that ribbon cable.

I bought this game at a flee market last saturday. The seller didn't want to sell the gameboy color and the game inside of it separately, so I ended up buying a gbc and pokemon red for a stunning 3 euro's! (The battery cover was missing though, but it works fine)

It's an alarm clock with a built in tv screen. You can choose to wake up to either tv, radio or a buzzer.