Nice cauliflower! I had to go read about the purple color on it. I've never seen it in the grocery store.
"Purple cauliflower's color is due to the presence of the antioxidant anthocyanin, which can also be found in red cabbage and red wine."
"Displaying vibrant violet hues, Purple cauliflower may be different in color than its white counterpart, however, on the outside, that is the only difference. The entire plant (floret, stalk and leaves) is edible. The stems and trunk are firm and tender and the florets have a dense yet soft and crumbly texture. It's flavor is milder, sweeter, nuttier and free of the bitterness sometimes found in White cauliflower."
http://www.specialtyproduce.com/produce/Purple_Cauliflower_1122.php