555 timer IC idea

[brett]

Check out the Modulatron for a switching application. 
The schematic below is a bit messy, but the 555 is used to switch between a signal and its inverse.  It makes a ring modulator, or "Dalek" sound.
The 4066 contains several CMOS switches.
http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=17571&g2_serialNumber=2
cheers
PS I reckon I could do this better, and with half the parts now.  But it's an example.