This Father's Day, let your dad know he can put the outside world on hold. If your dad's cell phone is usually an extension of his hand, then these funny Father's Day cards are a perfect way to say hang up and hang out. At least for 24 hours, dad should be on the do-not-call list. Let the boss call. Let the telemarketers squirm. It's Father's Day, and he doesn't have to answer to anyone – on the phone or otherwise.