Also available:

CCleaner Slim (No Yahoo toolbar)
CCleaner portable (Take it on a USB stick with you)

CCleaner is a freeware system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware! :)

This is the normal installer with toolbar.