MGM Grand Lion Habitat: The lion has been a part of the MGM heritage for many years, beginning with the legendary Leo, whose roars have welcomed generations of moviegoers to epics of the silver screen. Now visitors to the MGM Grand casino can see several African lions and cubs. The lions live in custom accommodations on an 8.5-acre ranch 12 miles from the casino but are brought into the hotel's habitat where 35-foot glass walls allow guests to view the lions from all angles. The area is open daily from 11 a.m. to 7 p.m.
Volcano at the Mirage: This is the freebie that really started it all. The volcano at the Mirage erupts at the top of each hour from 8 p.m. to midnight, spewing smoke and fire 100 feet above the water. But this isn't the same show from the casino's opening in 1989. The Mirage has joined forces with Grateful Dead drummer Mickey Hart, Indian tabla sensation Zakir Hussain and Fountains of Bellagio design firm WET to create an all-new audio/visual spectacle.
There are plenty of other free things to do in Las Vegas and the convention and visitors authority has a full list of all the free activities in the city.