Geekipedia
Wired recently launched Geekipedia. It lacks depth but the pitch is what really makes it work: "Wikipedia doesn't distinguish 'need to know' from 'didja know?' -- and it's lousy for browsing. That's why we created Wired Geekipedia. Godwin's law, Guitar Hero, Gates Foundation -- you may know their definitions, but we tell you what they really mean."