They're pretty easy to start. I used to start them in invidual pots (3-4" or so, whatever they fit in) and then transplant into the large pottery on the patio at planting out time. Plant the sprouted and unsprouted the same way. They should still sprout at 65 degrees, though they would sprout quicker if warmer. Can you put them near a windowsill - maybe a small table or even a chair by the sill so the sun filters down on them? That would warm the soil and the light would stimulate them to grow, too (I start my bulbs by the window - there's not a lot of sun, but enough). Don't water too much until you actually see leaf growth - keep the soil moist but not overly so, the tuber has to put on root growth first, and if no root growth and the soil is too moist, it may rot out on you. If they start to get leggy if not enough light, just pinch them back, same as you would any other annual.

Thanks so much for your reply. I wanted to get them going this weekend, so the information is very timely.

I'm out of small pots, unless I can find an old 6 pack or two laying around the garage. (which might be too small?) I'm thinking about starting them in small trays, perhaps making cardboard dividers to keep the roots from intergrowing too much.