managing RSVPs

Can anyone recommend a site for managing RSVPs?

Facebook seems decent, but not everyone has an account there. OTOH, since it's easier for everyone to get a Facebook account, it's not clear that anything could be better.

list of all threads

Java question: how does one access and print the list of all threads in the JVM?

static shocks

How hard (and how efficient) would it be to capture the energy of static shocks, to e.g. power my PDA? Today I've had several severe shocks without trying.