Finally! A roller coaster that doesn't discriminate against the height-impaired! This feat of engineering was accomplished by Dutch Lego enthusiast, Luc2000. The build features a five-cart inverted roller coaster that fits ten minifigs in each car with four minifigs "staffing" the ride. The most amazing part of the project has to be the half corkscrew. It's powered by one Mindstorms NXT unit and three NXT servo motors, with two touch sensors and one color sensor. The build took 3-4 months to complete (1-2 hours a day), and I say it was time well spent! [EuroBricks]
The video below showcases all of these amazing features (though, unless you're a fan of bizarre pop music I'd recommend skipping to 1:40 for the real action):
Want Lego to design a roller coaster? Then consider supporting the Cuusoo project. The model displayed on Cuusoo is a stripped down version, but that's understandable considering how expensive this set would be.