Have you ever thought about growing your own mushrooms? On Amazon right now you can get this fun Back to the Roots Organic Mushroom Farm for only $19.85 when you clip the $3 off coupon. I think this would be a very fun and educational activity for kids.
This will ship free with Amazon Prime or qualifies for free Super Saver Shipping with a $49 purchase.
Note: Amazon prices and promotions can change at any time. The price(s) listed in this post is/are subject to change.