Reddit mentions of Barefoot Books Yoga Pretzels: 50 Fun Yoga Activities for Kids & Grownups (Card Deck)

Not my situation so just spit balling ideas. Maybe look for a place close to home with child care at the gym. Even better if you can find other moms in the area, it can be like a play date for the kids while the moms work out.

Look for exercises to do with the kids, walking, biking, hiking, sports.

There are options out there for family yoga too (wish I could remember the name of the company, but there is one out there that makes cartoon cards for different yoga exercises to help introduce yoga to kids - found it randomly window shopping and my sister in law says her and the kis are enjoying it).

Edit: http://www.amazon.com/Yoga-Pretzels-Cards-Tara-Guber/dp/1905236042

My daughter (almost 4) likes Cosmic Kids Yoga on YouTube. A British lady wears a onesie and tells stories about animals through yoga. This is probably for your 6 year old only but honestly I'm not up on what 10 year olds like! She also has Zen Den on the same channel, which are guided meditations for kids, and we love them. That should be interesting for both kids.

We also have Yoga Pretzels, which is a deck of cards with yoga positions. You can create a flow with them, and there are some yoga games. My daughter is still a bit too young for this, but even so, she's learned about five poses now and likes to do the partners yoga poses she sees on the cards.