It has only been in the Olympic games since Sydney in 2000 and the keirin track cycling is amusing everybody.
A pace-setting motorised bike - called a derny - leads the cyclists around the track, starting at 15 mph and reaching 30 mph before exiting the race with just over two laps to go.
Then it all goes crazy. The cyclists begin sprinting (and often crashing) to the finish line.
Great Britain's Becky James secured her place in the final of the women's keirin but the event has got lots of new fans.
Keirin is the maddest and best thing in the world.
-- Kris (@k_d85) August 13, 2016
I listened carefully to the explanation of the Keirin cycling but it still sounds like when someone explains fourth cousins #Rio2016
-- Siobhan Synnot (@SiobhanSynnot) August 13, 2016
Viewers particualrly love the derny.
-- Leila Travis (@LeilaTravisTV) August 13, 2016
-- Who's asking? (@HaroldShand1979) August 13, 2016
-- The Baron (@20TheBarons) August 13, 2016
How do we get that job?
I want to be the guy on the electric bike in the Keirin. Looks like he's on a shopping outing....
-- EP Attorney (@EPAttorney) August 13, 2016
I so want to be a Keirin moped rider in the Olympics!! Why are these never advertised on LinkedIn?
-- David Wilkinson (@davidbwilkinson) August 13, 2016
goal in life to be the Derny in a keirin race ? pic.twitter.com/G1R2bhHsSx
-- söphie. (@_sophiemae_) August 13, 2016
World's best job is that bloke on the moped in the keirin. No effort, great view, comfy seat, no need for Lycra.
-- Dan Walker (@mrdanwalker) August 13, 2016
Hilarious but also dangerous. There seems to always be a crash.