I'm not the only one with a pi tattoo, I'm not even the one with the Greatest tattoo... But here they are:

This is mine

This is Ginger's

And this is Sara's.

Here's Derek's

And Nina's...

This is Ben's

and Marc's, in which the dots represent digits, starting on top and going clockwise

This is Kevin's, he's the singer of Tub Ring. Note the digits around his arm!

Chris has a nice one on his shoulder