Fastlap is a fun place to go with a group of friends. It's a lot better than those kiddie go karts at places such as Scandinavia. Karts can reach up to 25 mph, although it's difficult since the area isn't big which is why there are so many turns inside.
It can get pretty hot inside the warehouse in the summers, and it's about $15 + tax for 10 minutes of riding, but you can usually negotiate a better price if you have a bigger group.