I take a lot of photos out the window of my truck. Many of the birds that I see will fly away as soon as I exit my truck, so it is my mobile bird and wildlife blind. To allow me easy access to my camera(s) I made a couple of these. The clamp is from Amazon or you can find them at camera retailers.
Cup Holder Tripod Mount by Harvey Richards, on Flickr
Weapons of the Day by Harvey Richards, on Flickr