Vegas!

There is soooooo much to do in and around town it is amazing.

The Pink Jeep Tours - take you out for quad driving out in the desert

Las Vegas Cyclery has an off road cycling tour, they provide everything including a luncheon

Horseback riding also in the Red Rock park

Drive out to Pahrump for a Front Sight gun course or a real race car track experience

Boulder City for parachute jumping or if your are not that brave go to the indoor sky diving arena

Pick a concert, pick a show - some of the Cirque de Solie are very sinful

On Freemont street they now have a zip line, short but fun - I think there is a zip ine at Grand Canyon too.

More sedate is a paddle boat ride around Lake Mead

If you have kids, there is a cowboy town with a shoot em up show and a small zoo in Red Rock area.

Roller Coaster rides in NYNY or on top of the Stratosphere, also I think the "over the side" rappel is still happening at the top of the Stratosphere

A short drive out of town is Death Valley.  Not also to do, but how many people can cross death valley off their bucket list.  Plus there is the Death Valley nut and candy store there, delicious.

So there is the short list fer ya

I'll second  Death Valley.  We went for a day when we were staying in Vegas (we were using Vegas as a base for various hiking trips).  A bit of a long day, but we had time to drive there, do a couple of hikes (Gower's Gulch - which was PHENOMENAL, and the sand dunes), then head back.  There is nothing more jarring than walking through a casino when you have just come back from a day of near total silence..

Normally I hate this as an answer, but...

I recommend searching this forum for the word Vegas.  More than any other city, people ask this question all the time.  There are many good ideas out there.

Have fun!

P.S.  Why hike Red Rock when you can ride it?  McGhie's Bike Rental

Come to Boulder City and do a trail run in Bootleg Canyon.  Or you can run the Historic Railroad Trail and end up at Hoover Dam (7 miles round trip).  If you are looking for something really cool, check out the Flightlinez out at Bootleg Canyon (????www.flightlinezbootleg.com).  I agree that you need to check out Hoover Dam and the Pat Tillman Memorial Bridge. Take the tour of Hoover, it is amazing.  If you rent bikes you can ride the River Mountain Loop Trail, which is 33 miles and runs along various parts of the South-Eastern end of the Valley. If you want to mountain bike, Bootleg Canyon has everything from easy trails to hair raising downhill.  You can rent a bike from All Mountain Cyclery.  If you end up doing anything in Boulder City, the Coffee Cup from Diners, Drivins, and Dives on the Food Network is a great place to eat.  Milos a few doors down is a great place to eat too.

Yama Sushi is a tiny, hole in the wall sushi resturant.  It is great, but occassionally you have to wait up to 45 mins.  Just depends on when you will be here.  If you want to eat there, I suggest doing lunch, not dinner.  If you go for dinner, plan on waiting an hour or so.  If you like sushi, this is a great place. I was born and raised here, so if you have questions drop me a line.  I don't know everything, but I know a thing or two.