> Half past six, six thirty-five, six twenty. It isn't until we approach the next whole hour that we give it any credit: Quarter 'til seven.

It's sometime amusing to use the "half past" or "quarter to" form but not with whole hours. E.g., if someone asks the time at 6:35, you say "quarter to 6:50" or "half past 6:05". It can perplex people. (Best to only do this with people who already know you are a twit...).