iOS: The Do Not Disturb function in iOS 6 is fantastic, but one key feature it lacks is location-based blocking. Call Bliss is an app that adds that along with a few other handy tweaks.
Call Bliss works without jailbreaking by tapping into the existing Do Not Disturb functions. When you start using the app, you're asked to allow a new profile in the Do Not Disturb settings panel, and then you're good to go.
From there, you can create groups for each of your contacts, and then you can assign different groups to specific locations. For example, if you're at home, you can block calls from work, or if you're at work, you can block calls from friends. It's a simple set of functions, but it works well and makes Do Not Disturb much more useful.
Call Bliss ($2.99) [iTunes App Store]