Nemesis, Europe's first inverting rollercoaster This one is at Alton Towers, my local. Also home to Oblivion with the first 90 degree drop, Air with the first flying coaster and some other really quite crappy areas of the park for kids... GET OUT OF MY PARK, KIDS!
If you're ever in Las Vegas, don't forget to visit the Stratosphere Tower. At ground level its 3 rides would be the most boring rides in the world...but these rides are 900 feet high! Holy *&%# they're scary!