Enable momentum scrolling for Magic Mouse

The Mouse System Preferences pane does not include an option to enable momentum scrolling. The setting is a hidden preference. Use following command in Terminal to enable momentum scrolling.

defaults write com.apple.driver.AppleBluetoothMultitouch.mouse MouseMomentumScroll -bool yes

Revert to the default setting:

defaults write com.apple.driver.AppleBluetoothMultitouch.mouse MouseMomentumScroll -bool no

Screencast: