Oh, I hadn't seen this thread before (which is ironic given the subject). I've been needing glasses since the age of 4, moved onto contacts at the age of 11, but I wear rigid gas-permeable lenses, not the big jellyfish ones, mainly because that's all that was available at my prescription, which is basically anything beyond my nose is blurry.
I now carry spare contacts, spare spare contacts and have endless pots of old ones stashed in every place possible, the car, every bag I own, coat etc. The great thing about gas-permeables as opposed to soft lenses is that you can spit and stick if you need to take one out, it looks horrid popping one out, sticking it in your mouth, sucking it clean and then popping it spit-laden back in your eye, but in an emergency needs must (an opthamologist will now appear and scream at me).
Oh and Aaron, make sure you've got a spare pair of spec in your car/on your bike at all times. If you need specs in France, you have to have a spare pair in/on your vehicle everytime you use it; a speccy-friend was fined because she forgot her spare pair. 90 euros and three points, she wasn't happy.