AlienMelon did a project using flash to bring interactivity to video. If you click to the right on “Level 2” it’ll bring you to it. Clicking on “WHA?” brings you to the FAQ where you can bug the commander till he blasts you with his laser gun. Clicking on “PLAY!” you’ll find Alexis a tragic story of love and a limited vocabulary.
Currently I’m working on a short film/music video that combines blue screening and flash. If you are new to the land of chroma keying here’s a good article about it, and another one on lighting.