Ask HN: How do you find product ideas?

Hi HN, how do you choose the passion projects you are working on?

I just wrote an entry about how I find my ideas - http://first10.255bits.com/wordpress/2013/01/01/how-to-find-your-product-in-a-sea-of-prospects/

TLDR: I write down one idea a day as an exercise and then choose which idea to productize when I have enough time to implement it.