I've seen these around and really like the simplicity of them. Meet, the Bilibo. An award winning children's toy for ages 2-7yrs, the Bilibo's iconic shell shape and bright colors are said to invite a wide range of interpretations and encourage children to invent their own games, to play and have fun in an active and creative way. From rocking, spinning, and sitting to hiding under, carrying with, and peeking through, the possibilities are endless - use it at home, take it to the beach, in the water, even the snow!
I bought one for Harley for christmas (yay, finally I have started my shopping!), and also one for our godson's third birthday. I found them at Henry Hiccups, in Subiaco. Won't be testing them out until christmas time, but I think they'll be a hit.