Yep, it's called artistic cycling:

http://en.wikipedia.org/wiki/Artistic_cycling

together with cycleball

http://en.wikipedia.org/wiki/Cycleball

it's one of the weirder things to do on 2 wheels, but I happened to grow up with a competitive cycleballer as a neighbor (unfortunately he never won the world championships against the all-dominating Czechs), so I know almost all about it and I even went to the local club to try one of the trick bikes once when I was about 12.
When I tried to emulate those on my normal bike, I completely jammed the nuts on the back axle (sort of wing nuts? - stood on them as you'd do on an artistic bike)