Merlin Mann runs a site called 43Folders which provides "::A bunch of tricks, hacks, and other cool stuff"::.
It has a lot of useful stuff like Jase was talking about in his Organise your home article.
I particularly like Part II as well as Kick procrastination&rsquo::s ass: Run a dash.
Barnes and Noble University (online) is running a traning course on the Lord of the Rings and The Hobbit here.
Looks rather interesting.
I found a site that teaches basic electronic theory, which has always been an interest of mine. Be warned though, it is pretty heavy going and I had to stop after just 2 pages!!