How to tie a quick release double-knot in your shoelace

Starting from an untied shoe make an overhand knot as usual

Simple overhand knot

Next loop it around again just like you did before, it'll look like an overhand knot with three loops in it

Double overhand knot (three loops)

Now make the two loops of the bow just like you would normally tie your shoe

Normal 'double loop' bow

Now, just like for the first overhand knot, loop it through again! Then pull tight and your all set.

All set and lookin' sharp

This works really well for my dress shoes that seem to always come untied for no reason, but it doesn't hold up quiet as well with my running shoes, but still effective.