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Although my little Greased Lightning looooooves to paint, it isn't always convenient to drag out the paints and later clean up the mess. A quick alternative is water painting. By using a piece of colored construction paper and a bowl of water, he can enjoy the fun of painting and I can avoid the mess.
Sock sorting is another fan favorite. I stockpile all the unmatched socks for a few weeks and then let Greased Lightning and older brother, Blonde Warrior, race to find as many matches as they can. Admittedly, not much "matching" actually takes place. Some of the more colorful or patterned socks find their mates, but large quantity of all-white eventually just become an indoor snow ball fight...which is fine by me, because it keeps little hands busy and encourages a brotherly bond.