I think it'd be a good idea to push legislation prohibiting gays from adopting. And owning pets. And living within 1000 feet of a school or church. And driving. And voting. No, wait, I'm serious.
Outrageous legislation along these lines would force the proponents of gay-marriage bans on the defensive, make them explain how they don't want to deny rights to gays but marriage is different. Color me skeptical that they could avoid sounding bigoted and actually make a nuanced case against gay marriage. Including a few of the more inane laws that have actually passed in other states in this "bill" would make it more powerful. Whaddaya think?