Robert Smaus, the well-regarded but now retired LA Times gardening columnist, advised in early October, 2006 (http://www.latimes.com/features/la-hm-smaus5oct05,0,6059164.story) the following winter crops.
Many vegetables only grow, or grow best, during the cool fall, winter and early spring months. These include beet, bok choy, broccoli, Brussels sprouts, carrot, cauliflower, celery, endive, garlic, kale, kohlrabi, leek, head and leaf lettuce, mesclun mixes, onion, pea, radish, spinach, snow peas, Swiss chard and turnip. Most are easy from seed but cabbage, broccoli and other cole crops [Brussels sprouts, cabbage and cauliflower] are best transplanted into the garden so they can be planted deep enough to cover and support the bends typically found in young stems.
I think that arugula ought to do well too, given the leafy greens that are on the list.
I'm also about a month behind his suggested planting schedule, but maybe my proximity to the coast will help keep temperatures up for germination.