You should mention Skateboarding. Kickflips took years to catch on because people only saw Rodney Mullen in skate-shop distributed VHSes.
Torstein Horgmo debuted it in 2010: http://www.youtube.com/watch?v=pFGqkq3QqRE
And now they're expected at each X Games: http://snowboarding.transworld.net/1000194812/featuresobf/tw...
Tony Hawk's first 900 was pretty neat. He was getting close to doing it, but couldn't quite nail the landing and it was decided to let him just keep trying until he got it. Even though it was over regulation time and it took him 10 tries they awarded him first place and none of the other competitors protested: