was looking through the episode listing for the 3rd season beacsue the dvds are out tuesday, anyone know i was curious

I don't know, I guess they just didn't feel like making one,,,other ones are:

There is no Thanksgiving NOR Christmas episode for season 1,
No Christmas eppi for season 2.
No Thanksgiving eppi for season 5.
no x-mas eppi for season 7

I could be wrong but I think I'm right about this.