Best free activity on the strip!
Sometimes it's nice to get some fresh air and get away from the smoke and the slot machines. A nice walk to Bellagio to see the fountain show is perfect. I love that the fountains "dance" to the music. Viva Las Vegas was perfect!
At night it can get crowded, and people can get pushy, so I suggest arriving at the end of a show so you can walk right up to the ledge for the next one as people are leaving. Fifteen minutes isn't a bad wait at all. Bring the camera!