Have you ever read the book Wacky Wednesday by Theo. Lesieg? It is a great Dr. Seuss book about a little girl who wakes up and everything is wacky. Each page has the reader looking and counting wacky things from 1-12 and then on the last page there are 20 wacky things.
Looking this up on Amazon, it looks like it might be out of print but it seems there are plenty of used copies circulating.
To enrich this activity your class could have a "Wacky Wednesday" and wear wacky clothes like shorts over blue jeans and socks on pigtails. Turn posters upside down and put on some wacky music to do a wacky dance. They can also practice the letter "W" and then turn it upside down and practice an "M".
Here is a simple "W" worksheet from First-School.
It's late in the school year--time to get a little wacky!