I love using their prepaid envelopes to send them my nasty reminders that I am a Conservative without a party!
I used to do that too until I was reminded that fund raising operations pay people to open the envelopes, process the checks, make note of who sent the check for future fundraising, and throw the rest of that crap away. I get a kick out of the survey questions which always allows me to check the box that conforms with how I think. I try my best to target specific candidates with my largess.