Reading Usable Help
@UsableHelp on Twitter
Gordon R. Meyer
Edward Tufte's website has a fun discussion about Instructions at the Point of Need. A concept that is related to, but not as fancy as, contextual help.
For my own contribution, here's a photo of what a Panasonic projector shows when there is no video source connected to its input. The screen describes how to activate a laptop's video-out functon.