I've seen lots of small arcade machines on the internet (mostly made of GBAs or small portable emulator devices) and the idea cached my imagination. I wanted something similar which is both decorative and functional. With the help of my father I made the Tetris arcade which is a small, lcd game based, functional mini (14 cm / 5,5 inches tall) arcade machine. I choose the "9999 in 1 LCD game Tetris" because every household in Hungary hat at least 5 of them ( they are really cheap) and if I ruin it it's easily replaceable. (short closed the first one when it was nearly finished)
The outer shell is made of really thick cardboard and secured with small wooden rods and glue. The buttons are regular buttons expect the joystick, which is 4 micro switch secured together in a tricky way, I'll write about this later ( thanks dad!)
The buttons are connected to the ribbon cable (which comes from the screen) with the help of a small terminal connector. (see the pic). I soldered the terminal connector to the end of the ribbon cable, and this is where I attached the cables of the buttons. It's possible to make it this way because the input depends on which wires from the ribbon cable are connected together. For example if 1 and 2 are connected and the button is pushed down, it starts the game. The 5th and the 6th cable restarts the whole system.
As I mentioned earlier the joystick is really tricky. I attached a sketch (sorry, it's made in Paint) how it's assembled. it's actually just 4 switches and a flat piece of Lego (without edges) secured together with clips. (it's great because I didn't needed analog conversion for the D-pad). The rod of the joystick is glued into the hole of the Lego. I secured the 4 switches on a soldering board. I trimmed down the edges of a flat Lego piece and put it on top of the 4 switches. Then I took 2 gem clips (not the colored ones) and made an x like in the sketch. I secured together the whole joystIck with it, even made a small cut at the side of the lego piece just to make it more secure.
The batteries are held on a small "shelf" . I used the original battery holder of the game trimmed down to size.
it even has a LED light on top, and it looks really cool in the dark.
I replaced the speaker, too.
The decoration is cut out from the original packaging of the game.
UPDATE: I attached a video of it, check it out!
(sorry for my English, and if you liked it, vote for me at the Game.Life 3 contest!)