Volunteering as classroom assistant at a quilt convention/show is a great way to be introduced to new techniques. Volunteers usually don't take the class but they can sit and hear all the instructions and see the work.
One such group that regularily uses volunteers is The Original Sewing and Quilting Expo's. They have 8 events a year:
Fall: Chantilly Va, KC, Minneapolis and the west Chicago area
Spring: Fla near Orlando, Atlanta, Cleveland and Worcester Ma.
If anyone is interested you can check their web site.
I have vounteered the past 2 years here and thoroughly enjoyed it. I'll be teaching in Chantilly and at the October Quilt show in Atlanta this year.
It is a good experience.