The episode is being aired this Wed at 10pm, according to Tv.com, IMDB.com, and CBS.com.

As for why they didn't play it last week, perhaps there was some conflict (ie a baseball game), or sometimes, shows just don't play every single week just to extend the season longer (or mess with and anger the fans).

Hope that answers your question! :)

They didn´t missed the one this week. They just tried to get the crossover episode with miami and las vegas into one week :)
hope that helps :)

Yea they skip weeks sometimes. They do it in csi and glee and csi Miami they do it in a whole bunch of shows