Slow anything is beneficial as an antidote to our fast paced lives, whether Slow Food, Slow Yoga, or Slow Something Else. Slowing an activity delves deeper because there is more time to be attentive and reflective and experience what you are doing more deeply. I go to both Slow/Gentle Yoga and Yin Yoga classes and they are wildly different from the yang oriented vinyasa, power yoga or hot yoga practices that are currently so popular as an extension of the frenetic gym culture. In Yin Yoga, which is floor based, poses are held for longer periods of time, usually 3-5 minutes, and up to 10 minutes. The connective tissues have time to relax and stretch, encouraging energy flow and releasing blockages. Slow or Gentle Yoga, as its name indicates, takes it slowly and gently, and can be compared to a moving meditation. Breath is important in this practice. Both are calming and I usually come back feeling like I've had a spa session. Also check out this comprehensive beginner's guide to Yin Yoga.
You can slow any activity to experience a different spin on things. Try Slow Cooking, Slow Eating, Slow Teeth Brushing, Slow Showering, Slow Reading.