What is a good miniprep protocol for the class room?
The protocol I used in my genetics lab course was alkaline lysis followed by ethanol precipitation similar to this one.  Nothing terribly toxic or requiring a fume hood (at least at the small volumes used).

The more practical, reliable method is to use a miniprep kit (usually spin columns) from one of several suppliers (Qiagen, Promega, Bio-Rad, etc.) which are fairly affordable at $1-2 per prep.