I think that Speed the ride is the best coaster in Vegas in terms of quality. At the Adventuredome in Circus Circus, you can get a day pass for the entire enclosed theme park which has Canyon Blaster (a small and comparitavely smooth Arrow coaster). Manhattan Express at New York New York is pretty good, but its a TOGO (uncomfortable restraints and a bit rough). If wind conditions permit, you should check out the Stratosphere tower, the coaster is tame but the Big Shot is amazing. Other rides and experiences include the one at the Luxor (good), Star Trek: The Experience at the Hilton (good theming and atmosphere, but crappy motion simulation and overpriced), and the chariot race thing at Caesars Palace which is just okay, 3D headsets are bulky and are distracting. About 30min out of Vegas (south on the I15, near the border) at the Buffalo Bill hotel is the Desperado, an Arrow hypercoaster. The Desperado is the best full-circuit coaster in the area IMO (it can be shaky in some spots though, but no more than a woodie).
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Purple cows eat silver moon pies, among fiesty, glowing fireflies.