If you find a couple commercials on TV or radio that seem to be a match for your friend, then tivo or record them. Then, just transcribe them on your computer and print them out.
There are a few good books out there with copy and usable scripts too but the reads become stale if overused. Also don't be affraid to customize a few pieces. When creating a demo it's not always about bragging about a product you represented but the delivery and ability to grab attention, be real, conversatonal and believeable. If you want a few script to use send me an email I'll give you some good copy you can play with.