Not that I'm a stay at home mom but these are great ideas! The Stay-at-Home-Mom Survival Guide: Toddler Activities - peeling tape off the table (or fridge) develops fine motor skills (lots of ideas here)
The Ultimate Guide to Hands On Toddler Activities - Brittany Estes--- This could also work for pre-math skills. Which shape has more or less? I would put on magnets on the back and have a magnetic work space for them to do this activity!
Bubble mix doesn't last long in the hands of a child. Create a bubble station to provide a solution. This is so clever! / Only clever until the solution falls below the top of the bubble wand loop - then it doesn't work.
The Stay-at-Home-Mom Survival Guide: Preschool Activities This is a GREAT site. She has so many clever and easy ways to work with your preschooler and have fun at the same time. I'll need this for when I'm a stay at home mom :-)
Fourth of July Firework Salt Painting - Busy Mommy Media _ This is such a cool art project for kids! It looks so neat when it is done. I love that it uses stuff I already have on hand. This would be awesome for a rainy day activity!