A friend in my neighborhood told me about a bike trip that he and his wife took recently.  He mentioned that one couple used a tandem for the first time, and throughout the trip, many of the other couples were talking about whether or not this tandem couple would get a divorce by the end of the trip.  By the end of the trip, the tandem husband was calling out VERY specific instructions to his wife as to when he was slowing down, when he was about to stop, when he was turning, etc, and I bet their marriage was all the better for it.

I think a Tandem Tax would be a great idea.  Any couple that is engaged to be married is provided by the government a tandem bike on loan that is outfitted with a mechanism to ensure that the couple has put in their required miles together on the tandem before marriage is allowed.

From my own experience on a tandem with my bride, I would say this would be the best money the government has spent in a LONG time.  Time coordinating, talking, exercising together on a tandem is the best marriage counseling you could every ask for!