A Diablo 3 "God Mode" exploit was found, and quickly hotfixed by Blizzard, that made Wizards completely invulnerable. I knew I picked the best class. The bug was reported on the official Blizzard forums and was confirmed to be working within the game from a wide variety of users.
UPDATE: Several gamers are commenting on the official Blizzard forums that the bug has not been fixed. We've reached out to Blizzard for an official statement regarding the bug, and when we hear back we'll be sure to give you more info on what's going on.
UPDATE 6:30 PM 7/23/2012: Blizzard has finally released a statement regarding the bug:
We are currently rolling out a hotfix for a recent bug regarding invulnerable Wizards. We will continue to carefully monitor this issue and welcome anyone with information about bugs or hacks to submit a detailed report to our Hacks Team by emailing email@example.com, or by completing the Hacks Report web form. In your correspondence, please include any steps necessary to replicate the issue as well as any additional details you are able to provide.
The exploit only worked for Wizards, but you could play on either game mode (normal or hardcore) which offers unique conseqences in a game like Diablo 3. Check after the break to see what I mean.