I planted alyssum by accident this spring, thinking it was a different variety of flower. I'm oh-so-glad I made that mistake, though - it's bloomed since mid-summer, and only became prettier as the days grew colder. We had a hard frost last night which was tough on it, but I think it will last a little while longer.
Also, I called it "asylum" until three minutes ago. Thank you, Google, for correcting me.