Sprinkler! This will bring hours of fun for a 1 year old - get one of those little turtle shaped ones and stick your baby in a swim diaper - and LOTS of sunscreen - and play in the cool water.
We got a little blow up pool for the deck ($10) and a tub full of ducks ($12) and that brings hours of fun too. Heck you can even sit in there too! Grab some funnels and extra Tupperware and play, play, play!
The Park! We have a park here in town and they have a little play area with fountains - it was nice to see all the other kids in the park too. Careful of the pushy kids though.
While your at the park bring the kiddo to the park! The swings are fun and you can both go on the slide - yay.
That's all I have at the moment. I have more recipes coming soon just need to find more than 6 minutes to type =]