Do you have a patio or balcony?
When the boys were infants, I had visions of turning our apartment balcony into a play area in lieu of a yard, though we moved before it was necessary. The townhouse we lived in next had a slightly larger patio on ground level. Water play was one easy outdoor option:
|Tub play on grandma and grandpa's back porch!|
|Water play in the townhouse patio, just a plastic tub and random kitchen items!|
|Even if you don't have a yard, a kiddie pool and water toys can be done on a patio just as easily as a plastic tub, see below|
|Playing in a kiddie pool in their great-grandpa's patio in Wisconsin!|
There are many sources for weather-resistant "padding" or you can use an indoor/outdoor rug, if you're worried about new walkers falling onto the concrete (such as SoftTiles). A small climber (such as this one) would be great either on a patio or in a corner of the home for a little exercise and fun. Blowing bubbles and painting are great outdoor activities for older babies and toddlers that also don't take up a lot of space.
A friend of mine with triplets gave me the great idea of putting your little ones into swim wear in hot weather and then letting them paint old cardboard boxes outside. When you're done, just wash off the paint with water from the hose or a kiddie pool.
For more inspiration, check out my Pinterest board on the subject: Patio Play