Funky Stadium is a Battle Stage in Mario Kart Wii. It is a fully dirt-ground stage, with many boost pads on wooden ramps and half-pipes all the way around. There are many people watching you in the background, screaming and cheering when you make a trick. When the Pre-race Countdown Timer reaches "GO!" and the battle begins, you go down a wooden track littered with boost pads and no railings, and then go up the track again (as if it was turning into a ramp), and hit a boost pad and fly into the battlefield. This Battle is probably owned by Funky Kong, but you have to unlock him and because of the large size, it is the biggest battle arena in the game.
This battle stage is yet to appear in a future Mario Kart installment.
You can see the picture of Funky Kong.
A whole unused background is found in the game's files. It is found as dk_sora01! If you go to https://noclip.website. you can see the map of the course. Go to Mario Kart Wii, then funky stadium, Go to textures. and find dk_sora01!