Still in beta but with Tasker you can now screen and block calls!
Ideal for people dealing with unwanted marketing calls and such.
The nice thing about this is that you can configure it in such a way that for the caller it seems like your phone is ringing and he is waiting for you to pickup.
But in fact you don’t hear anything and so are not bothered with this unwanted call!

Until this version comes out of beta you can find out how to already get it here.

How to set it up:
In Tasker add a new Profile and select Event -> Phone -> Call Screened
Then add the conditions. But be careful because if you add it incorrectly you might block calls you don’t want to block!
If you want to block a specific number add a condition like this:
%cs_number EQ +4932221853008

If you want to block a range of numbers that start with the same characters (like a country code), add a condition like this (be sure to select as operator OR and not AND):
%cs_number ~ ~R\+216.+
So the country number is +216 and all numbers of that country will be blocked.
After adding all numbers or range of numbers that you want to block you will add the Task:

Give a name to your new Task and then add the action: Phone -> Call Screening.
Configure how you want. I left it as default which is that the phone will not ring and for the person calling you it seems like it’s ringing so he will be waiting, for nothing :-).

So in the end your Profile will look like this:

Your Event will look like this:

And your Task and Action will look like this:

Let me know if this worked for you as well or if you have questions! Email LVerduijn+Tasker@hotmail.com