In reply to LastBoyScout:
To tie your shoes so they don't come undone:
Basically tie the 2nd bow as a reef knot not a thief knot - chances are if this hasn't ever been pointed out to you, you've been tying your laces badly for the whole of your life! Very handy to know especially for under gaiters.
It simply requires a demonstration of reef and thief knot strength and a demonstration of how to do it on the double bow on laces - if you haven't done it before it can be strangely tricky to master even though it is dead simple.