marshmallows are a good companion to jello, as they are both made from horsie hooves...or something similar...

although there is a "health food" marshmallow made from Agar agar.

sometimes jello is made with less water, and this is used for crafts
projects or food that can be cut and formed (with cookie cutters, for instance)
http://www.cooks.com/rec/search/0,1-0,jello_jigglers,FF.html
that is for the kids, but for big kids, they prefer adding alcohol
--called jello shots--http://www.myscienceproject.org/j-shot-3.html

also used as a medium for art...
http://current.com/items/90416121_jello-shot-art-bill-cosby.htm