This is entirely way too tempting.

The last time my wife left town for a weekend, my son and I built a trebuchet in the driveway. I feel a new project coming on.

Knots

I spent the weekend tying knots. As fast as I could make a keyfob, they were gone. Taken by friends and family.

It's kinda fun.

Here's a blog dedicated to knot tying, with links, tutorials and a crapload of ideas.
More here(Turks's head and other decorative knots), here(chain sinnet) and here(Basic introduction to knotwork).