The fountains of Bellagio are pretty exciting, unlike the corporate-operated Bellagio hotel which is just okay.
The fountains come on every half hour unless it is after 8PM when they run every 15 minutes. This is a Must See in Las Vegas as just about everybody from grandpa, to teenagers to little children enjoy the spectacular show of lights, water and music.
The song and choreography is different each time (from singers like Celine Dion to Whitney Houston to Pavarotti), so you get a whole new show just about every time you visit. My personal favorite is the fountain show with Frank Sinatra's "Luck Be a Lady" as the song is classic Las Vegas and the show really fun.
The fountains are way better after dark!! You will know when the fountains start up even if you aren't looking at the Bellagio because besides the obvious music that is playing the water that shoots up in the air comes down fast and makes a very loud slap that echos off the walls of the Bellagio itself.