Regarding your doing things approach:

I don't really know what to do other than go look up events at Eventbrite and then aimlessly wander a museum for about an hour.

Yep, it's unlikely that you'll get to know someone if you spend your time at the museum alone. You'd have to actively approach people there, which might or might not be acceptable, given the context of your event.

I guess this works better if you're doing this with an active cohort of friends and not simply randomly crashing around as an individual stranger.

Exactly. It works even better if your activity is something that has you naturally interact with the other attendants. In fact, that is the whole idea behind the "do something" approach. That's why going to a museum (solitary activity) alone won't help.

I haven't specifically done the salsa dancing thing though.

Salsa is often recommended because (1) there are way more women than men interested in it, (2) you naturally interact with people, (3) there's close touch, (4) you learn a skill that makes you more attractive and (5) the atmosphere is light-hearted (rather than, say focused with a roomfull of boardgame nerds).

Mainly because I haven't had the opportunity to make such a regular committment.

And therein lies the problem. The "do something" approach really shines when you have a hobby where you can casually interact with people over time and get to know them in a relaxed setting, rather than having to ask out someone after a chance meeting that's unlikely to occurr again.