HMS Beagle and the Galapagos.
H/t to Carl Zimmer at The Loom for the great idea of asking if anyone had any scientific tats. Oh yes. I was there reading his Open Lab 2008 post 'Even blook flukes get divorced.' An excellent piece of science writing (although I am partial to the critters, having studied them), and I fully intend to read every one of the other 51 Open Lab 2008 winners.
While I'm delighted to see HMS Beagle on a fan's flesh, there is a protocol to these things. Sailors are entitled to a tattoo of a swallow for each 5000 miles sailed (although most make do with one to celebrate their first 5000). An anchor if you have sailed in the Atlantic. A full-rigged ship (such as Beagle under sail) is merited only if you have rounded Cape Horn. And if you want to earn that ink on the decks of the new HMS Beagle, you will have to help us with donations. Few will round the Horn on the Beagle's circumnavigation, so shake up any CEO aunts or uncles, or philanthropic millionaires in the family. Re-assure them the tat doesn't have to be big and vulgar, it can be hidden under clothes. And what changing room bragging rights that would give you.