And here I make my terrible unschooler's confession: I coerce them to do math workbooks.
Coercion never works. My daughter does the work because she wants to (she ADORES worksheets of any variety!) and my son simply refuses, while submitting to the odd worksheet, here and there, from which he gains precious little -- because it's coerced. BUT... as it turned out, he did manage to learn long division with the help of one of those pages, and, after months of constant prodding from his school-going friend ("did you know math is my best subject?", "I'm really really good at math, you know.", and "Do you even know what long division is??") he was so proud of himself that he went on to finish the section and is now working on measurement. Still. The spark of inspiration is definitely not there.
We've had some great conversations in our daily life, and there's enough interest in those (eg. exponential theory, physics, measurement, negatives and decimal theory), but the simple practice that seems to bring facility with those theories is definitely lacking.
We talked about alien technologies. You just never know where the light will come from!
Thanks to my brother, we ended up watching this movie about crop circles, busted out the compasses and graph paper, the rulers, and pencil sharpeners, and...
Voila: math is now unschooled. Er. I mean. Inspired.
You don't have to care about aliens or crop circles to find this movie fascinating. The forms and math involved, and the way they're laid out in the movie (with alien theory!) are pretty enticing.