How to build cool stuff: Instructables.com
Instructables is an awesome site of how-to guides.
From the Web 2.0 Conference:
Instructables is an awesome site of how-to guides. The content seems to be weighted towards clever and geeky projects rather than basic home improvement. While it's easy to find a lesson on how to paint your laptop lid, it's hard to find one on how to paint a room. Still, the design and layout of the lessons--most of which are photo illustrated--are beautiful.
New at Web 2.0: better collaboration features, so you can build lessons, wiki-style, with compatriots instead of building one yourself and relying on the comments to clear up your goofs. This is a great site if you think the 20-page projects in Make require too much commitment. See also: Wikihow.