I've had video tapped into the onboard navigation system (from an earlier modification/hack) for sometime now which is nice for watching movies and viewing the PC.  However the backseat passengers would have to watch video on the screen from the distance of the back seat.  We rented Animal Crossing to play on the Gamecube at home and the kids and I were hooked.  So we bought the game and started playing.  Well, my time on the Gamecube was few and far between with the kids playing all the time, then my wife created a character and started playing... the next thing I knew I was getting on around midnight and spending most of my time with Wisp the ghost.  So, I decided it was time to mount a rear video monitor in the car and add a Gamecube to the mobile video entertainment system.  

First step was to mount the drop down video screen for the backseat passengers.  I had the local sheet metal shop form a bracket from a pattern I gave them.  I was going to cover the bracket with headliner material, but after I peeled off the protective coating on the aluminum, I liked the look so I left it.
Wires for video, audio and power were run up through the dome light and down the pillar next to the front passenger seat.  I got the video monitor off of eBay for a great price.
I picked up a 4 device video switch.  Switch 1 is the DVD player, switch 2 is the Gamecube, switch 3 is for the PC and switch 4 is for a future option.
Next I had to cover the electronics.  I already had the modified AVC-RGB1 on the back floor which I was concerned about with people's feet walking or kicking it.  So, I drew up a template and took it to the local sheet metal shop and had them build my box out of steel. (Shown here with trim molding on the edges)
Next I cut out some auto carpeting and covered the box and carpet with spray-glue.
With the carpet on the box, I added door trim to the edges and installed the video switch to the box.
The next step was to install the electronics cover in the back of the car.  In the picture you can see the modified Pioneer AVC-RGB1 module that converts composite video into RGB video.  You can also see the Acura's DVD Navigation system under the passenger seat.  The DVD player for movies is under the drivers seat.
The cover is installed and ready for action.
Next I ran the Gamecube wires under the seats and carpet from the back of the car up to the front AV connection box.  I'm using the Gamecube auto adapter so I don't have to plug the Gamecube into the AC inverter.
With everything hooked up, the system was ready to go!
The controllers are the Nintendo Gamecube Wavebird wireless controllers. They work great in the car.