I read about traveling by freighter years before we had kids and thought it would be a great way to take an extended trip with an older child.
http://wikitravel.org/en/Freighter_travel

With the rise in piracy, I suppose I'm less inclined, although still quite intrigued by the idea.

When I first read the subject line of this thread, freighter travel was the first thing that popped into my head!

Being offended is a natural consequence of leaving the house. - Fran Lebowitz