We made this paint 'n popsicle stick flag this week. It was a simple enough craft to keep the interest of a four year old and match his ability. We painted 5 red sticks and 4 white sticks, and glued them onto two sticks in alternating colors. (It would have been nice to be accurate with the number of stripes, but it doesn't work with the popsicle sticks--makes too long of a flag.) After the paint and glue dried I made a blue box for A to fill in. We added white "stars" once the blue had dried.
We also wore our flag shirts and read the book F is for Flag by Wendy Cheyette Lewison. We had picked it up at Target a few years ago for $1 and it is perfect for introducing simple facts about the US flag.But there are several other titles out there, just run down to your local library and see what they have. Happy Flag Day!