Kids can't just do poses for four hours. Attention span, physical endurance, behavior issues all came into play. I have developed a bag of tricks I'd like to share with you all.
Each child had a yoga mat, and I started off with some basic warm ups not just to limber up, but to remind them of their "personal space". With arms and legs spread, we swept our arms around in an imaginary bubble. If two "bubbles" touched, the kids rearranged to make sure they had enough space.
We then began to go through poses. I have read many different kids' yoga books to come up with 36 poses that can all be named after animals or objects. The reason I did this is because I have a bag of little plastic animals and shapes that the kids use to learn from. They closes their eyes, reach into the bag, draw one out, then we learn that pose. Those animals are also good for Savasana breathing at the end: I place one animal on each child's chest and have them watch the animal rise and fall with their breath.
We did modified Sun Salutations. We did handstands using the baseball backstop. We did partner poses. We also did the three Warrior poses in a series I call "Flight of the Arrow" (I changed the names to "Archer" poses). We start in Warrior 2, "put your hands together in front, and draw back your bow". Then we "make the arrow" by putting our arms up into Warrior 1. "Place the arrow in the bow" (bend forward with arms parallel to ground, bent over knee) 
"then let the arrow fly!" by bringing the back leg up into Warrior 3.One thing that amazed me was the fact that almost every child could do Crow by the end of the workshop. And it was, by far, the most favored pose. As I said, poses are physically demanding, and frustrating for some children who are still learning balance and coordination. That is where some hands on stuff comes in!
The first activity we did was to review the poses using marshmallows and toothpicks. One large marshmallow, 6 mini marshmallows, and 9 toothpicks. After we assembled, the kids arranged the figure into yoga poses that they learned. The best part, of course, was eating the marshmallows at the end!
The second activity was coloring mandalas. I bought the stained-glass mandala coloring book by Dover publishing. Using markers, the kids had some quiet time coloring their mandalas to take home.Other things I did was teaching them about breathing, placing their hands on their chest to feel their heart, ribs, belly and how they move while breathing. I also made up a story with words that were the yoga poses they learned. As I said each yoga pose word, they were to show me that pose. I.e. "Then the EAGLE landed on the TREE."
I had fun and plan to continue this workshop for years to come.
Jaycie