There's bumperstickers:
If you see one stuck on somebody's forehead that means they are part of this board. Once I get some more decal paper, I'll print some and give them away to anybody who wants one. My email: cactus2clouds at yahoo dot com
Or you can download this:
http://www.geocities.com/cactus2clouds/images/MSJ_info_bumpersticker.jpg
and print it on a t-shirt or hat. The url should probably be underlined, with some extra space underneath.
Or...if someone wants to design something....
As for something more general and subtle.... how about a spider web? Or "www hiker," "www climber," etc.
Jim, I notice your church group logo comes on a spaghetti tank. Has that been a popular item?