They're about 4x6 laminated cards; the front has a picture of the ancestor,
their name, and their relationship to my kids (eg; great-grandmother). The
back has their "stats" - birth, death, marriage, parents -- and a couple
interesting facts about the person. The idea is to spread them out on
the floor/table and match them up with parents/spouse/child to form a
family tree.
My kids enjoyed them -- although probably not as much as I
enjoyed making them! Lol! Here are a few samples:
http://www.rootsweb.com/~gamadiso/tradingcards.htm