Halloween can get pretty wild and crazy in Vegas and the atmosphere is one big spooky, sexy party. Several of the nightclubs hold huge costume blowouts complete with prize winning costume contests. Some of the events during Halloween are Ghouls gone wild at Harrah's, - the only outdoor Halloween party, Studio 54's Nightmare on 54th Street, or Jet Nightclubs Halloween Ball at the Mirage. With the risqué nature of this town expect to see some pretty sexy and exotic costumes. If Halloween falls on or near a weekend, rooms may be harder to get or more expensive and nightclubs will be packed.