That's correct: anybody can give a talk, and unprepared talks are explicitly welcome.
Japanese kids going on their first errand, as discussed at the meetup: search for Hajimeteno Otsukai
Just my particular results.
For those of you still waiting, got an email to the effect of: We did it, sorry it took so long, it'll be uploaded in 3 weeks. Also they said that more than half were not yet done.
Every 3rd meetup is board games: there's generally dominion, Zendo fairly common, and often one "long" game going on sort of on the side.
I think I'm probably missing some common games that I don't pick as much...
Not sure I've got a good source for you, but if you use the Rayleigh criterion you get that you can just about make out earth-sized objects using visible light at 4 ly. You could use much higher energy photons (better resolution from lower wavelength), but this gives you other problems. Anything beyond visible light won't make it through the atmosphere (1 km is a BIG thing to put into space), and x and gamma rays are really hard to build optics for.
Submit suggestions here