While many of the videos can also be found on YouTube, the great thing about Grokker is that you can filter down the type of workout (or cuisine) you're looking for. I'm always interested in neck and upper back videos, because DUH.
This one is an 18-minute video led by Erin Motz, who has a friendly, helpful demeanor. This isn't a fancy video -- it's basically one static camera -- but it's clear and concise (except for that common "my left your right" stuff that doesn't translate) and I really felt some good stretching in my neck and shoulders.
The video is part of a 30-day challenge, but you can jump in to any video you want.
I'm embedding the YouTube video, but I greatly encourage you to check out the Grokker site because there are a load of videos you can watch and save for later (after you sign up).