The Belly Button of Buddha will be the last episode aired, as Nick GAS shuts off on a Figure it Out episode at 5:59:59AM EST, on 12/31.
Therefore, The Stolen Arm of Shiva/The Stone Marker of Leif Erikson will not air.
How was that precise time determined?
The N takes over at exactly 6:00AM EST. Therefore, NICK Gas shuts off somewhere around then. Maybe not exactly 5:59:59. I'm just feeling like that I guess today.
Heh... I actually meant like, "On what site did you find that GaS was leaving at 6:00AM?" but Wikipedia has it, so I answered my own question.

I just realized something, though. I'll have to look into it...
Alright, so, I live on the west coast. I haven't confirmed this in a while, but I'm pretty sure that Nick GaS is synchronized across the US, so that a show that I watch at 2:00PM in PST is the same that you watch at 5:00PM in EST. In other words, there is no delay between east-coast airing and west-coast airing. What's the problem then? The N does
not synchronize its airing schedule, to my knowledge. So a show I see at 2:00PM PST is the same one you see at 2:00PM EST. How will the transition take place then? Will my channel switch at 6:00AM PST or EST?
I really don't want to wake up at 2:55AM to find out, but I'm sure we'll find and answer. Then everybody will forget about it for the rest of the world's existence. And then I'll realize I just spent so much time typing a post that has no real significance. And then I'll realize that my addiction to the show never had any real significance either. And then I'll realize that I spent four years making a website that could have been used to create world peace. And then *gets shot*