It was just last month AppCap made it's way into the BigBoss repo, offering the ability to block application use with a variety of means and filters. This can be a lot of help when trying to stay productive at work, and you need a quick and blunt reminder to stay focused!
The real part to this tweak that makes it shine is the flexibility and amount of options it offers. The developer had pretty much every idea in mind crafting the filters for blocking apps. You can choose to block the app with these options: the time of day the app is accessed, minimum time/duration between launches, the days of the week, and even restrict the launch by what wireless network your device is connected to. AppCapPro still is hindered by its' limitation of how many apps the tweak can access, with a "cap" of 5 applications.
AppCap (free) in the BigBoss repo provides the same functionality, minus 4 apps, allowing only one application to be limited.