If you head south from Las Vegas, not towards California, but out of Clark County towards Arizona, Highway 93 takes you over one of the most amazing engineering feats ever, the Hoover Dam. If you are sick of the glitz and the glamour of Las Vegas, a perfect getaway is the concrete and grandeur of the edifice that provides power for much of the southwest. Even if you don't have a car, Hoover Dam tours that leave right from the strip are a great way to check it out.
There are lots of different packages you can get, some cheap, some not so cheap, some requiring reservations, and others which you can just grab a ticket and head out. A great starting place is Shop.vegas.com, which lists a number of carriers. The choices are many. You can just head out and back (about 45 minutes each way) and take in Hoover Dam itself, or you can combine it with a number of other sites, including the Ethel M chocolate store, though the connection between the two is beyond me.
When you get to Hoover Dam, make sure you take advantage of the tours. They have a film that explains how it was built, which is interesting more for the technical set. I went with my Dad, an engineer, and he just kept mumbling "See what engineers can do? They change the world!" No Dad, I'm not going back to school. As for the tour of the facility, if you don't get a guide who makes the joke about the best Dam tour around, get your money back. It may not be Hoover Damn tours, but they use the wordplay to their advantage.
Admission to the Discovery Tour when you get there is $10 for adults, and kids under 6 are free. If you are driving your own car, it's also $5 to park, but in all it's a great tour, and a marvel of modern engineering. And I'm still not going back to school.