A fun and simple oral motor activity that kids love is a bubble factory.  All you need to make it is a straw and a clean empty yogurt cup.

 To make it cut two holes in the top of a yogurt cup:

Cut a small hole on the top of the lid and a larger hole on the bottom. Fill the yogurt cup half full of bubble mix. Insert a straw in the small hole and let the child blow bubbles. If you are worried about the child sucking up the bubble mixture, cut a hole in the straw about one inch down. This will keep them from sucking up the bubbles.