Here a little tool that may not be very useful (Apple rejected it for not being very useful) but maybe someone likes the idea. It just blocks your keyboard input so you can wipe over your keyboard in order to clean it.
Full Specifications
What's new in version 1.0
General
ReleaseMarch 11, 2011
Date AddedMarch 11, 2011
Version1.0
Operating Systems
Operating SystemsMacintosh, Mac OS X 10.6, Mac OS X 10.6 Intel