Check out the Cabo Wabo bar and club. Great food, awesome tequila.
The Giggling Marlin is always fun, a little trashy, but fun for sure. Great place to pick up college co-ed or cougars on the prowl.
Sqid Roe is a popular club for dancing.
Couple other big clubs in that area.
I'd spend some time on the beach for sure. You can pick up some green or white from dealers on the beach if you are into that. Cuban cigars everywhere and of course good tequila.
Go fishing if you have the time. Not sure if its Marlin season now, I think it is, and when they are hitting there is no thrill like it.
I rode some ATVs around the desert too, was fun, but you can do that in many places. Only do it if you have some extra time.
I'd check out neighboring San Jose Del Cabo too, its small, authentic feeling, quaint, and has some cool shops and a laid back feel.