On Sunday, my roommate Brendan and I escaped Salt Lake City for a short trip to Las Vegas. The 6+ hour drive was interesting because I-15 descends into Arizona's Virgin River canyon, which was quite impressive. The first night we visited 17 of the major casino resorts, on foot! The second day we visited the Hoover Dam and re-visited some of the casino resorts' attractions.
We had a great time! (The absence of an open container law helped.) The whole trip was pretty much unplanned aside from the hotel reservations, which we changed mid-trip anyway. I think it's best to approach a trip to Vegas unplanned. I mean, it's impossible to get bored even without plans, so just go without plans and just let it flow. That method served us very well since I probably did more in 72 hours on this trip than any other trip of even greater length.