In honor of St. Patrick's I also experimented with making Green Beer. It's about as low-tech as you can get. Add a few drops (1-2) of green food coloring to the bottom of a glass and add beer.
What's it worth? Just about nothing. It might look interesting, but it doesn't add anything to the beer. All you'll get is green teeth, a green tongue, and probably some green food coloring stains on your fingers or your favorite shirt.
If you choose to make Green Beer for your holiday party, take this advice: Don't.