My favorite free attraction in Vegas. Yes, even beating the street people giving out cards with naked women on them J/K ;p
The Fountains of Bellagio are located in the heart of the Strip, where visitors can enjoy a beautiful display of water being shot high into the sky, in tune with music.
http://www.vegas.com/attractions/on-the-strip/bellagio-fountains/
Strolling along the Strip, especially at night, it's a great sight to behold, whether with friends or your significant other. Last time I was there, we saw the Fountains with Michael Jackson's "Billie Jean" playing. Later on, on the way back to our hotel, we saw it again with Celine Dion's "My Heart Will Go On". Such an extravagant spectacle for the senses! There's just something about an oasis of moving water right before your eyes in the middle of the searing desert, music tickling your tympanic membranes. All for free!
Great views from the front of Bellagio, or when dining at Mon Ami Gabi at Paris. The show runs every 15-30 mins, with the start times depending upon the day.
You can't miss this attraction at the Strip, literally & figuratively. I know when I'm in Vegas again, I'll certainly enjoy checking out the Fountains of Bellagio several times more.
Highly recommmend!