M.L.
You can make leggo goodies out of graham crackers and m&ms. Tint the color of frosting (gel works better than liquid food coloring) to match the m&ms, frost small sections of graham crackers and add the m&ms (letter side down) 3 in a row to look like leggos.
You can use a frosting that dries to put several in goodie bags.
This is a super cute leggo party, including printables to put on cupcakes or goodies bags:
http://www.livinglocurto.com/2010/06/lego-birthday-party/