Did you know that you can freeze mushrooms? I didn't, but you absolutely can. I went in with a friend to buy a case of criminis at a really good price. We love mushrooms at our house, but there was no way that we were going to eat six eight-ounce containers of them in the couple days they would stay good in the refrigerator. Because of the high water content, they don't freeze well raw, but after slicing and sauteing in butter until they released most of their liquid, they did really well. I defrosted a bag this weekend to test them (in a risotto with Gorgonzola and peas -- Yum) and they were no worse for the wear; still a little meaty and with great flavor.
Getting the mushrooms ready to freeze was also a great Montessori-inspired practical life activity for Silas. I set him up with two bowls (one for the caps and one for the stems) and he had a lot of fun popping each stem off.