I would find very interesting to have the option of blocking "some" calls from certain hours of the day or night. I have some "friends" that are calling at bad hours and I would like to be able to "filter" those calls by the time of day or night.
I even consider that as a part of security to be allowed to filter by time. It's non only a nice feature, but an essential one, that I think is quite simple to implement, that would allow more control on the blocking feature.