My teenage son is currently 223rd in the world in Super Mario Bros with a sub-5 personal best. He's explained just bits and pieces of the SMB speedrun subculture to me (frame rules, etc.) and it's just fascinating.<p>At under 5 minutes, it seems like it's the ideal length for practicing as well - if you screw up a full run, you at most have lost 5 minutes of time, you just start over again.<p>No-warp runs which go about 20 minutes are way more painful when you make a dumb mistake in 8-4.