Now I see why the black friday sale is 4 days long...

spoomeister

...because it looks like everyone and their cousin is trying to buy zen, so the servers are just hamster'd.
Seriously, I've been trying to purchase zen in-game on and off for about a half hour now and the server times out every time.

spoomeister

...and of course, right after I post that, it occurs to me to buy it thru the Microsoft store instead. D'oh!