I love nothing more than sending my littles outside on a warm day and providing an experience or activity that will keep them engaged and busy for a LONG time! Here are some of my favs:
Take on old ice cube tray, ad a different paint color and water mixture to each square. Add a small or large popsicle stick into each square (small stick for bigger hands, large stick for smaller hands) and freeze overnight. Take outside with a large piece of paper taped to deck, table, fence, and voila!
Tape a large piece of paper onto a fence, and provide your littles with paint and/or spray bottles filled with paint and let them go to town! The longer/larger the paper provided, the longer they are kept busy trying to cover the whole space!
A for of my littlest dude, filling a large tub or bucket with soapy water, providing brushes, sponges and clothes, and you have your very own truck/car/dinosaur/rock/doll washing station!