At LCA 2004 Andrew Tridgell gave an excellent presentation on his junkcode directory. A few snippets from the presentation

Most programmers write bits of junkcode at one time or another. It's an important part of learning to 
be a better programmer.
...
In this talk I hope to convince you to value your junkcode, and to keep it rather than deleting it 
when it has served its initial purpose. Today's junk can help you build tomorrows killer app.
...
Your junkcode directory forms a type of toolbox.
...
Instead of telling people “I once wrote a program that does that” I can say “here is a program that 
does that”. A great way to impress the boss!

You can download the entire presentation here.

Im sure many of the participants in the room who hadnt already created a ~/junkcode directory immediately found this talk extremely high value and busted open a shell running `mkdir ~/junkcode`. I know I did.

To this day i still use my ~/junkcode. Although I'm not as game as Andrew to publish it online Ive stuck it in a git repo which I pull and push from various machines.

Ive found it an invaluable part of my toolbox as a programmer and consider myself fortunate that I was able to attend a talk that certainly has provided me with a life long lesson.

If you havent already created a ~/junkcode directory, bust open that shell, run mkdir ~/junkcode and jump on the junkcode bus today!