The Face Off extension for Firefox let’s you turn off 3rd party Facebook applications.

Oncee installed, Face Off will remove all 3rd party Facebook applications from any profile page you view. This can help you view your friends profiles without having to scroll through a lot of additional content you may not be interested in, or may not be appropriate for your workplace.

Future versions will give you the option to select applications which are still displayed.

Update: Due to changes in the code for Facebook, this Firefox Extension requires an update to work properly and is not currently available for download.

Facebook has also taken steps to improve their profiles and added profile clean-up and extended profile features. These have removed much of the requirements for the Face Off extension, and it I currently have no plans to update it.