Las Vegas is my favorite place to vacation and it remains one of the top tourist destinations in the world.  I have gone there 2 or 3 times a year and always find things to do that don't involve sitting in a casino.

Some of the favorite things to do that don't cost you anything are:

• Dancing waters at the Bellagio, which runs nightly, every 15 minutes
• The Bellagio also has the indoor solarium, which is constantly changed to matched the seasons or the holidays.
• The Fremont Street Experience, where you look up at moving pictures set to music.  Every night, on the hour, each hour is a different theme of music; disco, 50's, rock etc
• At the Rio, look up to watch the parade attached to the ceiling.
• MGM Hotel and Casino has the lion exhibit, where you can see trainers interacting with male and female lions
• Stroll the Forum Shops at Caeser's Palace
• Circus Circus runs free circus acts through most of the day
• Browse through M&M's World, located by the MGM
• A walk through New York New York will make you feel like you really are in the Big Apple
• The same could be said for a walk through the Venetian
• Treasure Island has the Pirate Show right on the Strip and runs several times a night

I know there are more and the best thing to do is to ask around; the front desk, employees, other visitors.