Wildlife Habitat Garden Tours
A number of Audubon chapters conduct annual wildlife garden tours. One of the longest-running is Tulsa Audubon's Wildlife Habitat Garden Tour and Plant Sale, now in its 15th year. You can see a map of this year's route, along with photos of some gardens on their website.
A few other Audubon chapters and organizations with web pages highlighting their garden tours include:
Audubon Society of Northern Virginia (see news story here)
Audubon Society of Western Pennsylvania (see news story here)
Fort Collins Audubon Society (see news stories here and here)
For info on putting together a similar event in your area, see How to Organize a Garden Tour for Charity and additional guidelines from Canadian Gardening Online.