Anti RoboCall Phone
I hate getting robocalls from telemarketers. I wish someone would build an answering machine that won't ring the phone if the caller is not listed in your address book.
You would enter the names and phone numbers of all your friends and relatives (well, most of them). Then the device would check the caller ID with the phone numbers in the list. If the caller is on the list, the phone would ring normally. If the caller is not on the list, the phone would not ring at all. Instead, it would take a message. It would be a bonus if the device would also display a list of all the phone numbers received that were not in your address book. That way, you could quickly scan them and delete them instead of listening to each one.