I got very involved when one of the SF actions just happened to fit my circumstances (that was the 7SN project last year.) There is a major SF action coming up very soon - like a week or so, I believe - in Texas.
I definitely recommend signing up to take part in any SF action that appeals to you. Some of them appeal to me more than others. If you see something you want to be part of, get in touch with staff and sign yourself up.