Do you have issues with certain Japanese characters not appearing in Mail? Are you frustrated by Safari's inability to access secure sites when parental controls are turned on? Or is your system having trouble starting up with more than 64 GB of RAM? If you answered "Yes" to any of these questions, you may be interested in the OS X 10.8.2 Supplemental Update 1.0, currently downloadable from the App Store.
This 27 MB Mountain Lion 10.8.2 patch fixes the three specific issues listed, and does require a restart. Macworld notes that there's also a 10.7.5 Supplemental Update in the wild, which addresses a Time Machine issue and a problem with Developer ID-signed apps failing to launch.