This is a good example of serving a niche: Carl Zimmer's Science Tattoo Emporium. It features scientists and their tats.
I (a science writer) wondered aloud if scientists had tattoos of their science. The answer was yes, and this site is the evidence. I'll be adding a new tattoo every day until I run out (if that day ever comes). If you want to share your own scientific ink, send it to me with some explanation.
Kind of cool. I've placed "getting a tattoo" on my bucket list. Hey, it had to have something and this was an easy one to steal straight from the movie. Of course, I have no idea what tattoo I would get, and I figure the longer I wait the shorter I'll have to live with the consequences of a bad decision. I'm thinking I might be getting my tattoo post-humously.
I do have to admit that I am partial to the idea of something from science. Pictured is my favorite from Carl's site.