Add an additional magic word requirement for making a trac account
It's clear that the spammers are solving our recaptchas.
We could ponder switching to some different captcha mechanism, but I doubt there are great ones out there that are usable yet also not broken by spammers.
Given the success of our cypherpunks option, I bet we'd get a lot of mileage out of a "say the magic word" step in making an account -- and the magic word, like the cypherpunks option, can be in plain view for a user who bothers to look.
I'm not sure if this will want a new trac plugin or what though.