You can see here the free buttons that I'll be giving away at San Diego. These are "band button" size (one inch round) and a very popular at shows. I rarely bring any home, and see them pinned all over people's shirts and bag straps. I've designed a new one this year, and will still have some of the older pink design available, too. I'm man enough to wear pink, although not often, but I wanted something a little more boy-friendly, hence the blue background version.
If you're going to be at Comic-Con, or some of the other shows I'm doing this year, be sure to come by and grab a couple.