Trail Type is a site showcasing loads of examples of type found out on the trail. You probably thought there were only a couple standard fonts used by Forest Service and National Park organizations, but it turns out there are loads of different examples of handmade, routered-into-wood, and quickly made letterforms, and they're all beautiful.
FontAid is a charity project where 27 designers came up with a font, and proceeds from the sale of the font are funneled to UNICEF to help war refugees. Cool idea.
Can't remember what that font was on your last project? Looking for a font that's grundge, or one that's high tech looking? Point Central has the best font database I've seen.