The Spark Bang Buzz website has not been updated in a while (it posts that the last entry was August 2004) but there is lots of neat cool stuff there.
Among the entries are these examples:
- A Propane Powered Lawnmower
- A Homemade Photocell
- Extracting odd sounds from salt water and Aluminum
- Making your own Vacuum Tube
Fun stuff -- I'll be trying the salt-water/Aluminum sounds in a few days.