Heath Ledger turned up, did that, and now every comic book villain is just trying to keep up.
Fun fact: "Heath Ledger locked himself in a hotel room for six weeks to develop the Joker's voice and mannerisms."
Somehow a fully grown adult doing tricks on a tiny bike is one of the coolest things going.
Fun fact: BMX racing heats last about 30 to 40 seconds, making it one of the shortest Olympic events.