Puddle jump. Go ahead — get wet. See who can make the biggest splash, jump across the widest puddle, and be the first to fill up her boots.
Create a “tie-dye” craft. Do the first part indoors: Grab some coffee filters and have the kids color them with markers (not washable ones), and lay them on a cookie sheet. Then put them outside in the rain and watch the colors run. Bring them inside, and after they dry, the kids can make flowers: Pinch each filter in the middle and twist, then wrap a green pipe cleaner around to make a stem.
Take your kids on a “rescue the worms” walk. (You don’t have to touch ’em!) Stroll around the neighborhood and let your kids pick them up off the sidewalk and toss them back into the grass. When you’re home, go to Yucky.discovery.com and search for cool info on earthworms.
Do a rainy-day Monet. Head outside with some sidewalk chalk. When it’s wet, it works almost like paint!
Have a splash. Take a bunch of bath toys outdoors — boats, buckets, cups — and play in a puddle, or find a “stream” at the edge of the street (if you live on a safe one) and race a boat against a lightweight ball.
Make a rain catcher. If you just want to stay inside, have your child decorate a two-liter soda bottle, and measure and mark half-inches with a Sharpie. Then you cut off the top and put it outside a window where you can see it from inside. Set some fun goals: “When it gets to half an inch, we’ll play a board game. When it gets to an inch, we’ll make cookies…” etc.!