Knotted Shoelace Aglet

Failing all other methods of aglet repair, the shoelace end can simply be knotted tightly to at least stop it unravelling. This doesn't aid lacing, and in fact prevents re-lacing.
Step-by-Step Instructions
Step 1

Tie the end of the shoelace with a stopper knot, such as a “Figure of Eight Knot” or a simpler “Overhand Knot”.
Wikipedia: Figure of Eight Knot.
Step 2

Trim the loose ends of the shoelace close to the knot for a neat finish.
Technical Information
Advantages & Disadvantages
Although this method is cheap, easy, durable and quite effective at preventing the ends from fraying, there are a couple of disadvantages:
- It shortens the ends, which may make it more difficult to tie the shoelaces;
- Unlike a normal aglet, which normally assists with passing the shoelace ends through the eyelets when lacing or re-lacing, this technique actually prevents lacing or re-lacing, as the knots generally won't fit through the eyelets.
Interestingly, the latter can be turned to an advantage when kids are learning to tie shoelaces, as it helps prevent those ends from being accidentally pulled through the knot (when tightening) or out of the eyelets (when loosening).
Visitor Feedback
I thought I'd mention something I've done when aglets become worn or fall off. I simply tie a very (and I do mean VERY) tight overhand knot at the end of the lace. For decoration you can let the a little of the end stick out and fray like a tassel. The disadvantage to this is that to unlace your shoes, the knot in the end of the lace may prevent it from passing through the eyelet, requiring cutting the lace. I've never had this fail before the laces wore out.
– Jason D., Texas, USA, Apr-2006