Hitchhiking on Sailboats
One of best things I learned from 31 months on the road is that you can get on a sailboat and explore great expanses of the world for free. This was explained to me in one of those carpe diem drunken bar conversations that magically change your path for the better.
Soon after learning this I spent the 3 months hitchhiking the South Pacific on a couple of different boats, exploring both deserted and inhabited islands, eating tons of fish, tropic fruit and french bread (French Colonies always have the best bread), and learning lots of little tips about life at sea. Did you know you could preserve butter by keeping it salt water? Raw eggs can be kept for months if you flip them upside down every couple of days or cover the shells in cooking oil.
There are a lot of websites and literature devoted to sailing around the world on other people boats (www.sailingnetworks.com is a good one) but the real challenge is making sure you find people that you're going to get along with. A night of heavy drinking with you potential crew-mates can usually speed up this process.