Hi....I have done MANY 1 1/2 to 2 hour workshops for students of all ages. It was also very successful with 'multi-generational' students (for instance, 10 year olds and 70+ year olds together.
I call them "stick masks". It does take a lot preparation before the class and fits well into the time slot you are interested in.
You start out with 'pre-cut' ovals (out of poster board or even cardboard), with holes for eyes punched out. I take many boxes of materials, such as feathers, yarn, colored markers, old jewelry, old glasses, leather, beads, etc and a hot glue gun. Studfents first draw the faces on the 'pre-cut' ovals and then glue on or otherwise attach the decorations.
When finished and decorated, glue a stick to the back of the mask (I use dowels that you can find at the hardware store) or sticks if on limited budget. The students can then hold the mask up before their faces by the stick held in one hand.
These masks are quick, inexpensive and fun to make. I teach numerous classes like this in libraries, schools, community centers, etc.......they also make wonderful exhibits when finished.
Good luck.
Juanita
wmstudio@flash.net