J.P.
My twins also started walking at 10 mos last April. We mostly let them run around in parks and playgrounds. When it was cooler or rainy we went to the indoor playgrounds that some malls have. They love that still. Since they are still pretty small and wobbly at that age there is not a whole lot they can actually do other than walk and eventually run around. Even an open field can be fun!
Updated
My twins also started walking at 10 mos last April. We mostly let them run around in parks and playgrounds. When it was cooler or rainy we went to the indoor playgrounds that some malls have. They love that still. Since they are still pretty small and wobbly at that age there is not a whole lot they can actually do other than walk and eventually run around. Even an open field can be fun!