Updates:
Break a bone: have not gotten particularly close. I am going on a decently long road trip soon, so maybe there's some chance of getting into a car crash?
Get married: not close at the moment, but I intend to do this within the next 1-10 years.
Defend my PhD thesis: I've started my PhD degree!
Visit Africa: not currently planned. I think the first "nonstandard" place I'd like to visit is Central Asia.
Win elected office: I did consider running for a Massachusetts State Senate seat if I didn't get a research position, but I got the position and so never ended up filing.
Get sentenced to >1 year in prison: I'm not committing any crimes in the US; maybe if I go to some random country with a different judicial system this could be more relevant, but I'm not planning on it.
Own a >1000 gallon aquarium: I have previously owned a 36-gallon aquarium, but I don't really have a house/a permanent place to live in, so this seems unlikely, at least over the next year or two.
Win a major fencing competition: I've fenced once in my life, and for a brief moment I was up 1–0 against the winner of the youth olympics in foil. (I then lost 1–13).
Die: I am not currently planning on it, and am in good health. However, I am going on a ~1000 mile road trip soon.