don't forget the election as well. and you are 100% on the number of episodes castles got 23 this season but there's only i think 2 or 3 episodes of (2012) left i believe than after the new year the new ones start again. "CSI:NY only have 18 episodes like last season for some reason?
and that shows going to have long breaks as well. my guess when it comes to grey's it'll have a couple episodes left before the end of the year and we don't get any until after the new year. this is only a guess on my part mind you.