Here's a rather interesting suggestion from the Motion Picture Assn. of America, via BoingBoing.
Apparently there's a rulemaking process for the Digital Millennium Copyright Act (the law that, for better and for worse, limits what average consumers can do with digital copies of music, movies, TV shows and software) going on right now in Washington and educators are asking for an exemption to rip DVDs for classroom purposes.
The MPAA's response seems to be that teachers should play DVD clips on a TV and use a camcorder to record them on a new tape they can play.
Of course, camcording is one of the top ways movies get pirated in theaters and has been regularly attacked by studios. And it's technically illegal for you or I to record a DVD playing on a TV and then use that tape for our own purposes, be they nefarious or not.
But I guess giving teachers the OK to break the security code on a DVD is the worse of two options.
Vimeo has a somewhat amusing video of an MPAA rep showing how it's done.