It looks like that mystery update for the Xbox 360 is causing some of the next-gen consoles to lock-up. No official word on why this may be, but the official Xbox Forums are starting to seethe with posters complaining about the dreaded ring of red light. Here's just one sample:

FFS why do microsoft force us to update.

my xbox was fine until the march update now it freezes up after 10 mins of gameplay

why cant they just leave it alone they should have held off releasing this piece of junk until it was ready.

anyway off to ebay i go and sell my 360 i cant be arsed with this forced updates its nothing but trouble

I'll see if I can raise some sort of official answer from my channels and update later today.

Update: Larry "Major Nelson" Hryb was kind enough to respond to my annoying bleatings about this. He says that while the crashes appear to be coincidental, team Xbox is investigating to be sure.

Update Crashing Xbox 360 [Xbox Forums]