I found an older thread on reddit today that asked the question of divorced people if there were any signs from the beginning that their relationship was doomed.  It was a great read with a lot of different answers.  One of the things that popped out was the canoe test.  It's where you can gauge how long a couple will last after seeing how they handle a canoe trip.

If you've never been in a canoe with someone else, it takes a lot of team work.  It also takes clear communication under some stress.  The couples that work well together and are on good terms at the end of the trip generally fare well in the relationships.

The couples that end up in the water, soaking wet, and upset with each other don't do so well.

That's the general consensus of those on reddit.

The Reader's Digest also did a story on this and say that it hasn't been scientifically proven, but it's still seems to hold pretty true.