Re: Las Vegas?
Cirque Du Soleil is awesome. My wife & I agree that we've seen too many of them to be truely "awed" anymore, but if you've never seen a Cirque show, you'll enjoy. I've heard "love" which pedro linked above, is the best of the group out there. I haven't seen it, but O was very good, can't remember the name of the other 2 that I've seen out there. There are a lot of good entertainers/comedians out there, so if Carrot Top isn't your thing, just look around, you'll find someone you'll like.
If you're not a gambler, spend a morning going out to the grand canyon. Place is impressive, there are numerous tour groups going out each day.
Hit "old" vegas for an evening. The light show on freedom street is pretty cool, the casinos are a little run down compared to the strip, but offer cheaper gaming options.
Ever play craps? Find a casino that is running a teaching lesson on the game, I think New York, New York runs 1-2 sessions every mid morning, I'm sure most other casinos do the same. Its a fun game, plus its nice to learn something new. Although be prepared, money moves quickly in the game, its nothing to be up $200 or down $200 in a 20 minute span unless you play very conservatively. But even if you play conservatively, the action around a craps table is fun to take in, and no body cares if you're just betting the pass line and nothing else, or don't want to throw the dice.
Bring walking shoes and walk the strip. Its always been very safe, but due the scale of all the building, what appears to be a 5-10 minute walk often turns into a 30 minute venture when you realize how spaced out everything is. The venetian is fun to walk thru, they have gondala rides if that is your thing, or you can just walk thru it. The Hardrock is off the strip a bit, but offers an interesting scene. The Forum shops at Ceasars, Bellagio's fountain show and glass sculptures are a must.
Is music your thing? There's the house of blues at Madalay Bay which might have an interesting show, some big names perform out there regular that no longer tour coast to coast (like Garth Brooks, Celine Dion, etc...) No matter your taste, there's bound to be something up your alley in town.
There are great restaurants all over, great steak/seafood places in each of the large casinos. The buffets are generally solid. Food is expensive out there, at least in the casino's if you're willing to venture out you can find some pretty good deals off the strip, where perhaps the car rental idea would help out.
5 days is a long time in vegas, budget accordingly. Plan some things that can stretch out the time/cost. Grand Canyon as mentioned above can be an all day thing. Hit a sports book, drop $10 on the Reds, watch the game and collect the free drinks. Lounge around the pool, enjoy long dinners/lunches, etc..