While perhaps not as glamorous as say, anything on the strip - Hoover Dam is worth the trip.
I had never realized the water was the main reason for the dam, not the electricity. +1 for education baby, yeah.
Its a pretty impressive spot, sited between two sheer faces of Black Canyon. The bridge they are putting in over it only adds to the wow factor of mega engineering projects. I wish they had a set of stairs or elevator so you could check out the whole thing from river level, that would be cool.
Some of the tour vids were a little too hyberbolic for my tastes, but over all its worth taking it just to see the belly of the beast.
Oh, if you plan on taking the tour, leave your food in the car. We lost our yummy organic trail mix at the security gate. Damn them!
(har har)