Contact sport on roller skates where half the fun is seeing what names people pick for themselves.
Fun fact: The original 1930s roller derby was one of the first professional sports to pay men and women equally.
You pay five grand for suspension and disc brakes specifically so you can ride down things that'll wreck them.
Fun fact: The sport started in 1970s Marin County with riders racing modified beach cruisers down Mount Tamalpais.