Mal, there are a great number of weekend party hot spots in Las Vegas. Expect to pay a $30 to $40 entry fee to enter the best o them ... and dress to impress.
Holloween weekend so expect te best of them to be crazy and loads of fun.
You'll most likely end up in the club closest to your hotel but here are a few of the best up and down the Strip and a couple less than a mile west of LV Blvd.
The Palms (west of the Strip, less than a mile) has a couple of great night clubs to meet the ladies including RAIN and GHOST BAR. You might want to start off the evening with a few drinks at the Playboy Club at the top of the Fantasy Towers. You can buy a Palms All Clubs Pass for about $60 to $80. Each club will have a Holloween costume contest with many thousands of dollars awarded for sexiest outfit, funniest outfit, scariest, etc; so be prepared to see some wierd shit in all the clubs.
Some of the top clubs along the strip are XS (unfooking real), Tryst, Tao (look for Snookie and Situation), Club 54, Jet, PURE, and the new nite spot in Aria. (And there are others.)
Expect to pay at least $15+ a drink. Also ask about Bottle Service if you have money to burn.
Clubs don't usually fill up before midnight and you'll more than likely see the sun in the sky when you leave.
Have a good time. ..It's LV and they expect that.