Don't have an LCD projector in your classroom? Have access to a TV with a pretty large screen, even an old one? Then you are all set.
There are devices available that will enable you to show what's on your computer on a TV. You need a PC to TV VGA converter. You plug in your PC video output and audio output into the device and then the other cables get hooked up to your TV. This enables your whole class to see what's on your computer.
I helped one teacher her set that up in her room. She had a very old TV, but we were able to do it. Now she doesn't have to try to sign out a multimedia projector, she just uses the old TV.
Saves money and recycles an old TV.
The converter boxes range in price from around $40 to $100. Wal-mart, Target, Best Buy, Tiger Direct, all carry a version of them.