Click to see Spoiler:
Episode 5.6 will take place a NYC comic con. Jonathan Frakes will direct and have a cameo role. Ed Quinn of Eureka will also guest star.

The other one, I don't know the date or episode number, will feature Kate's father, Jim Beckett, and the rumor is there will be some interesting action between him and Martha, as in a Meet the Parents type thing. Might also be some romantic sparks there, too. I'm very intrigued.