Verizon's at it again. I was really looking forward to blocking mode with the jb update, but they decided not to include this in the settings. Its actually hidden. However, you can still get it. This is part of the new software and not an app or 3rd party.
First down load this app from the play store.
Search for blocking mode.
Click on the first one. There should be two.
Rename it. I chose "blocking mode "
A shortcut is now created on the home screen for blocking mode!
Update: this creates a shortcut, but unfortunately its not fully functional. Post if you've found a fix please...