May one play Draidel with his wife when she is a Nidah? (sources please)
Should be pretty much the same issue as playing Monopoly or Scrabble or whatnot with your wife. (Unless you argue that the traditional aspect to it makes it less problematic, which I don't particularly hear. Then again I'm not crazy about the whole dreidel thing anyhow, and will refer you to the responsum of Chasam Sofer lamenting that this holiday is "celebrated" by gambling.)
Shulchan Aruch says one should not engage in s'chok or kalut rosh with one's wife when she is in a state of Nidda. Loosely translated as "playfulness" or "lightheadedness."
Contemporary authorities differ on something like playing board games, and may vary from case to case (e.g. playing at a table vs. lying down on the floor); though the interpretation of Shulchan Aruch I heard from Rabbi Yaakov Hopfer of Baltimore is that s'chok and kalut rosh means: behavior that is suggestive or disinhibiting.
The view you'll hear from the yutorah world is that it depends on the norms of gender relationships in your community. If sitting down and playing a board game would only be done as a prelude to more intimate activities, then no it shouldn't be done. If it's no big deal, then it's no big deal.
The Debreciner in Shaalos U'Tshuvos Beer Moshe Chelek 3 Siman 123 says that the Minhag is to allow one to play Dreidel with their wife while she is a Niddah. However he recommends making a Heker* - either by each one using their own Draidel or any other type of Heker. If the entire family is playing and they are not sitting next to each other then you can even use the same Draidel.
*Heker = An unusual item that is out of place to serve as a reminder of the changed status (in this case, Niddah)