Mexican Wave
The 'Mexican Wave' or as we know it today as just 'The Wave' is when crowds at sporting events rise up and down from their seats in a continious pattern all around the ballpark. Although 'The Wave' was popular in the late 70's/early 80's with colleges. It became popular in the 1986 World Cup which was held in Mexico.

This from a website visitor:
The Wave and Mexican Wave need improvement. It's rather lengthy, but try this: Two men claim credit for the first appearance of "The Wave" at a sproting event. The first is George Henderson, the "Krazy George" who had led cheers at professional baseball, foorball and ockey games around the United Stated since 1967. Henderson says that he invented the "Wave" during a nationally televised American League baseball playoff gane at Oakland Coliseum between the Oakland Athletics and the New York Yankees on Oct. 15, 1981. The other claim for the first "Wave" is by Robb Weller, former University of Washington cheerleader and one-time host of TV's "Entertainment Tonight." Weller's story is that during the Washington - Stanford football game on Oct. 31, 1981, he instructed the Huskies fans to stand up and raise their hands in first one section of the staduim and then another until a complete circuit was made. Henderson's tale of the origin of "The Wave" is the most likely as both the taped telecast of the playoff game and th 1981 Oakland A's highlight video (which includes a segment showing "The Wave" occuring at the October 15 game to back him up. University of Washington fans claim that Henderson's version wasn't a true "wave." In 2002, Hungarian university researchers announced that they had studied videos of 14 "waves" at large Mexican soccer stadiums (where the action is known as "La Ola"). Their paper in the scientific journal "Nature" claimed that "waves" usually roll clockwise acorss a stadium at a rate of 40 feet per second (about 20 seats per second) and are about 15 seats wide at any one time. Source: Answer Line with Michael E. Newman in Northen Virginia Journal, Vol. 66, No. 161, 08/13/04 That said, let me help a little on "Elvis has left the building" with this: In his early days, Elvis was performing on "The Louisiana Hay Ride" and got quite a reaction from the kids in the audience. They would
scream so loud, you couldn't tell if he was singing or not. The screaming usually continued long after he ended his part of the show. One time when he completed his set and left the stage, they wouldn't stop. Fearing what would happen if his fans got to him, he left immediately, but the kids continued screaming so much, the show couldn't continue. His manager finally ran out on the stage, grabbed the microphone, and shouted, "Please calm down! Boys and girls ... let's have a little quiet. He's not here anymore. ... Elvis has left the building."