Bring in some pieces of thick cloth, enough to blindfold a few of the children. Ask them to draw something (themselves, an animal, etc). After they've done it blindfolded, take off the blindfold and draw what you asked them to again.
Create an I Spy bottle (Voss water is awesome for this because they are a perfectly round bottle can be found for about $1 at Winco Grocery Stores)
Bring in some magnifying glasses and objects to look at.
Make fun binoculars out of toilet paper or paper towel tubes.
Create a fun color wheel on a large poster or create individual ones on paper plates. Bring in a bunch of different items that match the colors on the color wheel. (Preview Source)
Play a game of Hide and Seek with a favorite stuffed toy. (Preview Source)
Bring in random objects from home and place on the table. Take turns finding the....apple, fork, crayon, etc
Play Follow the Leader. Leader does an action (jumping, patting tummy, make a monkey face, etc) then all the kids do that same action.
Blow bubbles and watch where they go.
Watch your animals grow
Bring in colored cellophane and different pictures. Put the cellophane over the pictures to see them in a different color.
Create a pattern using Legos, wood blocks etc. (red, red, blue, green, red, etc) then have the kids copy your pattern.
Create rubbings using your hot glue gun! Create smiley faces, animals, letters etc on sheets of paper using your glue gun. Let dry completely. Using regular printer paper let the kids put their papers over the rubbings to "transfer" the images.