A wiki travel guide! Wikitravel.org is creating a free, complete, up-to-date, and reliable world-wide travel guide. So far they have several thousand destination guides and other articles written and edited by Wikitravellers from around the globe (some of whom just sit at home describing what's good about their surroundings).
One of the more interesting project goals is to create destination guides which are useful as print-outs, i.e. not always linking to sub-pages, but distilling the most useful information about each travel destination. For a good example see the "destination of the month" on the main page