I love my yoga and it is surprisingly relaxing. I've even started to relax enough that I doze off during shavasana.
Here are some links to Lululemon's free yoga videos on
youtube, they range in length from a few minutes to almost a 1/2 hour. I really enjoy the detox yoga and do it at night before I go to sleep, it makes me feel very sleepy. A few are aimed at runners but the "anytime" ones are great and the runner ones are equally yoga like.
Also there's a link to Yoga journal's free online videos. You can pick an area or kind of practice you want to do that day and they have both long and short practices as well.
My favorite DVDs include:
Yogaworks for everybody: AM/PM which includes short routines for AM/PM and a 45 minute beginner class and Yogaworks: Bodyslim which is more like a vinyasa flow kind of class. The videos tend to emphasize setting up each pose, which helps remind me what I'm supposed to be doing and the beginner one is laid back.
If you're looking for some other free options, sometimes iTunes will put free yoga videos up under TV episodes (Exercise TV had a good 10 minute relax and stretch one on iTunes) and then OnDemand on cable usually has some as well and if you're near a Lululemon store they do free classes once a week depending on the locations, which might possibly work with your schedule.