An absolute must watch if you've never been to Vegas. I think my first trip we watched the fountain shows about 10 different times. This last trip we only caught it once, but we always have to see it. They perform every half hour during the day, every 15 minutes at night, and the show is choreographed to different songs. If you can, catch both a daytime and a nighttime show, because the effect is totally different. It's also cool to watch from the observation deck of the Eiffel Tower. After a long day of walking around or clubbing or whatever, it's so relaxing to just sit here and watch the fountains dance. I love it!