DO NOT TURN ON YOUR PS3s with or without an internet connection.
An issue that causes games to not be playable that use trophies as a reward system was thought to be caused by a firmware update has been confirmed to not be a firmware issue. It is an issue with the internal clock reading the date as Feb 29’th. This causes issues with any game that has trophies. As far as a solution, the PS3 should fix itself within the next 24 hours with hopefully no lasting effects.
Again, even if you do not have your PS3 connected to the internet, DO NOT TURN IT ON TODAY!