Michael Garnier tried a lot of different businesses in his life, but it wasn't until he started building treehouses that things started clicking. On his 37-acre property in Cave Junction, Ore., he opened a bed-and-breakfast, but nobody came. Then, after building a treehouse for his kid, he got the idea to build a treehouse B & B — for adults. “I built it, and they started coming.”

Ten treehouses later, Garnier is now the owner of Out ‘n’ About Treesort and Treehouse Institute (www.treehouses.com). The ten treehouses that make up the Out ‘n’ About compound are all wired with electricity and are heated, but only about half have running water and toilets. The units range from 100 to 400 square feet in size.

Garnier is also the founder of the World Treehouse Association and host of the group's annual conference. Every Columbus Day weekend for the past eight years, 40 to 60 treehouse enthusiasts from around the world come to Garnier's “treesort” to learn the latest in treehouse design and building techniques, attend workshops, and learn how to climb trees.

Aside from the conference, Garnier hosts weddings and even meetings. He is currently building a lodge with meeting space to accommodate small groups.