1. Although 3-D has thrived in theme parks and on IMAX screens, last weekend's top opener, Spy Kids 3-D: Game Over, is the first studio feature to use the technique in years.
2. Technically known as stereoscopic cinema, the effect is achieved by shooting a movie with two cameras placed a certain distance apart. Those funky glasses then correct the double image on screen, making it look like one.
3. The 1952 Robert Stack adventure flick Bwana Devil (the movie everyone's watching in that famous LIFE magazine photograph) kicked off a 3-D craze that included House of Wax, Kiss Me Kate, and Hitchcock's Dial M for Murder.
4. James Cameron has said his next movie will be 3-D.
5. A 1960s variation, Smell-O-Vision, employed tubes to pump aromas directly into theater seats