So, we finally did it. We've made t-shirts available! Here is the link to the "It's like a sports bar, but with graphs" shirt, and here is the link for the "Vim" shirt.
A couple notes. First, both shirts are available in both green and white (I didn't realize that would be an option before; white is a little cheaper). Second, because these are custom-printed, you get your choice of shirt type as well. For the two folks who made the winning suggestions, I'll be following up with you to get you your shirt.