I've introduced multiple families to Settlers of Catan and it has consistently gotten rave reviews (and they're not just fluffing me, because months later they ask me about expansions for it etc.):
Anybody who lives H.P. Lovecraft and Cthulu stuff will probably greatly enjoy Arkham Horror, a cooperative game in which the players try to beat the evil descending upon Arkham before they die, or go mad.
