I need an adjective that implies that the person is profound/thought-provoking but not in a serious way, sort of like the narrator in The Hitchhiker's Guide to the Galaxy.
The words I've found (insightful, provocative, etc.) suggest that the speaker isn't humorous, which is very important. For example, 'Sally is a [word] young woman with a lot of good ideas.'
The word should probably be a little more academic and less conversational.