What might cause mouse and keyboard freezes after updating to OSX 10.8.2?
Several users have found this to work (and as far as I can evaluate, it fixed it for me as well):


Log in/switch to an administrator account
open Terminal
sudo rm /Library/LaunchAgents/com.google.keystone.agent.plist
sudo rm /Library/LaunchDaemons/com.google.keystone.daemon.plist