One wheel bike riding
 

Probably not a good idea.

https://www.youtube.com/watch?v=HT9f0bv3Eck

Why do they have to do that crap on the freeway? Have had it happen to me a couple of times in Dallas, when like 100 of them pour onto the freeway in front of me, then go 30 miles an hour while the front guys do their tricks. It's hilarious how they think they can intimidate a 1 ton 4x4 with a tiny little sports bike. Turn on the exhaust brake and then get 6 inches from their rear wheel and let off the gas. I wished I had a dash cam to record the fun

I admire their skills, but seems like they should keep it in parking lots.