High idle after starting and short drive?

[EnlightenedOne]

This just happened a few minutes ago. Was out driving for awhile, parked the car, ran into a store, came back out, started the car, drove to the edge of the parking lot and was waiting to turn out on the street. When I stopped and had the clutch pushed in I noticed I could hear the engine sounding louder than usual (I had the windows down). I look down at the tach and see the car is just "idling" at about 2000 RPM. Almost as if I had my foot on the gas or something but I didn't. Anybody had this happen before? First time I've seen this behavior.