If you're not already covering it in scouting or some other group, you may want to make sure your boys know how to tie a knot...as it's the kind of thing that a man finds useful from time to time.
You could even work it into a ceremony, requiring them to learn and/or demonstrate it.
Here's a list of the 10 most useful knots. I'm sure a quick trip to youtube will get you all the instruction you need...
How to Tie the 10 Most Useful Knots