The factual website How Stuff Works has a great article on How Lightsabers Work. Very informative, and very useful for those technology users who always wanted to know.
I like the pictures at the end -- and I want a saber toaster-slicer for my bagels.
Speaking of which, they do have a saber toaster-slicer in The Hitchiker's Guide To The Galaxy too.
Light sabers would be cool. They could also be used to open those impossible-to-open condiment packs whose manufacturers did not provide a nice little tear spot.
More information about text formats