When school doesn't look like school

Earlier this week, Queen Mom came in, bearing gifts.  One was a card game where the players have to pick up cards based on matches or on arithmetic (for instance, if you have an 11 and there are and eight and a three on the table, you can use the 11 to pick up the 8 and the 3.)  So, since the Things played several rounds of this game, I let them skip math that day.  Hey, practicing addition with cards is math.
Or a belated present for my homeschooling comrade in arms N.  N. brought a paper-making kit, so I figured, "hey, it's sort of like science and art.  We're learning how paper is made, decorating it, and having fun."
Now paper-making, lemon batteries, and card games are not on my curriculum or IHIP.  However, they are a means to an end--learning.  Not to mention a great way to keep my kids from watching TV now that winter is here and it's too bloody cold to go outside.