Welcome to the Official Redemption® Message Board!
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For a plain-old boardgame, Monopoly.
Despite its simple rules, it's difficult to pick up on the strategy when you learn it, so most of the people whom I've taught are reluctant to continue playing.
I have the same struggle with teaching people Redemption, I'm good, they're new.
Not Board per se, but I just played Munchkin, and it was a delight.