It looks like zombie yoga won't be happening again this year, but you can still get your yoga on this Halloween. A couple of cool-sounding events; let me know if you hear of more and I'll post 'em.

Halloween Midnight Yoga Fest at Laughing Lotus
It's a deluxe version of the studio's usual Friday evening Midnight Yoga. Show up at 9pm for free tarot readings, parade viewing (they're right off the Sixth Avenue parade route) and treats. At 10pm you can show off your tricks in a vinyasa class with live musicians.
To sign up or get more info: laughinglotus.com

Halloween Open Mic Kirtan at Integral Yoga
Yeah, you read that right. For this new event you can "Dress as your favorite singer/songwriter and come out to lead a chant." The event starts at 8pm and a $5 suggested donation includes refreshments.
Here's more info.

UPDATE:
Here's another event:
Punk Rock Yoga at East West Yoga
Kick some asana with this lively class on Halloween.
Friday, October 31, 8:30 – 9:45 pm. $19

And in case you're feeling nostalgic or missed it, here's some pretty great video of zombie yoga from 2007: