Spiderwort, I think

I think that it is an allium.
Allium
Which is similar to chives and a member of the onion family. Does it smell onion-y?

Lilies of the Nile, I think. They’re planted all over the SF Bay area, I think because they’re drought-resistant.

http://images.google.com/images?svnum=10&hl=en&gbv=2&q=lilies+of+the+nile

I think planetknit is right, it seems to be an allium–thank you. I had thought alliums were always purple. I’d only ever seen giant ones blooming as a round ball all flowering at once, rather than unfolding day by day by degrees going upwards the way my little one does, exuberantly throwing its blue arms outward like a little kid running to their mommy to jump up into her arms. But then, I’d never gotten a chance to see one growing in my own yard before. This is a cool little plant, I like it.

We have some Lilies of the Nile, and this is similar, but the flowers are just different enough.

Thank you everybody for the leads, I had a lot of fun looking at flower pictures and plotting future plantings!