If you stay on the West side of the Rhine you can visit the "world's largest free-hanging cuckoo clock"

http://www.youtube.com/watch?v=CP_0IIU-ac4

and, while you're there, there's a splendid restaurant just up the hill in the Burg Rheinfels with smashing views of the river.

http://sr47.de/t/pics/8259ddad92.jpg