- math olympiad
- unsolved problems in computer science
- the x-games
edit:
I would posit a 4th category (Sinners in the hands of an angry pRNG) as related but distinct from math olympiad

edit:
I would posit a 4th category (Sinners in the hands of an angry pRNG) as related but distinct from math olympiad
#2 if there's rng manipulation (cryptography problem), #1 if it's pure probabilities