If you ever have those times when you just don't want to (or can't) talk on the phone then you'll want to take a look at Call Blockr for BlackBerry 10. The native application does exactly what the name suggests, but with a simple (yet attractive UI) and some sweet timing features built in. 

With the app open you'll automatically see an on/off toggle for blocking phone calls. With this turned off your status will be displayed in green above the toggle showing 'Allowing Incoming Calls'. But switch that toggle to on and the status message will change to red in color showing you that it is 'Blocking Incoming Calls'. 

I think my favorite feature of the app is Scheduled Blocking. Here you can choose between two times that you want the application to be active and you even get a 'Calls Blocked' counter at the base of the display - with an easy one touch option to reset it. 

Due to restrictions from BlackBerry themselves there isn't yet the ability to block just certain numbers, but fingers crossed that will come in time. One last bonus is the Active Frame. If you have Call Blockr running you'll be kept up to date with any calls as the Active Frame tells you your status and if any call have been blocked - a nice touch. 

A sweet little application which will serve both consumers and business users well in my opinion. You can pick up Call Blockr for all BlackBerry 10 smartphones and the app is priced at £1.50/$1.99. 

More information/Download Call Blockr for BlackBerry 10