For The Girl, there have been no incentives (that I know of), but one of the elementary schools in the area produced a music video for all students taking the TCAP. She came home Monday talking about it and insisting I watch it. It get's long and repetitive towards the end, but The Girl really liked it:
The same people also produced a video last year for the CSAP test which The Girl got to watch. I like this one better. Maybe because the music is more from "my time":
I never knew about these motivational videos about state assessment tests, but looking through YouTube, there seems to be a lot of them.