I hope I'm not breaking any rules about commercial items on sale but this is kind of fun... it's a bubble level that tells you how steep that last leg burner hill was. Mount it on the stoker's bar for some extra moaning action. And, since it's German, it must be accurate! Find it at Sky-Mounti Inclinometer.
Mate, you can even link to it if it's an item of interest. You just can't pitch your own stuff in the general forums. You'll need that red star to profit from Bike Forums, but it's always free to help out other members.
I had a similar device in my Landcruiser. I called it the barf-o-meter. Ideally, you have one on the door, and one on the dash. I had one on the dash. Passengers never really appreciated seeing how far over the vehicle could lean. Long travel suspension with excellent articulation made for queasy co-pilots.