The idea of "flashcards" may make you think of endless drilling or rote memorization, but they're a great teaching tool for a wide range of ages and really fun to make games out of. Or, of course, you can hang them up as decor.
Canon's Creative Park is filled with patterns and instructions for toys and decorative items you can print out and assemble. They're quite amazing, but have always looked beyond my patience level. So I was glad to find that these flashcards and matching cards which can simply be printed and cut.
Here are the links to the sets above (bookmark this for a rainy day!):