Any ideas for toddler/preschool aged physical play sessions in the group ex room?

Any ideas for structured play for toddlers in the group ex room? Not necessarily for fitness of course, but for a place for toddlers and their caregivers to come for physical play during cold winter months and/or INDOOR mommy and me fitness that is fun for both mommies AND little ones. e.g. can we use steps without risers as a balance beam, make some games with the swiss balls, etc. Ideas? Programs? Inspirations? Tips? Success with gym-based kids clubs in the group ex room?