Cousins of cabbage, Brussels sprouts are actually a subspecies of Brassica oleracea - the same species of plant as broccoli, cauliflower, kale, collard greens and kohlrabi (in the same way all dogs are subspecies of Canis familiaris). Brussels sprouts were selected for their small, tight and sweet buds, whereas broccoli was selected for its flowery buds and cauliflower for its color and tight flower.
They are very versatile and can be eaten raw in a shredded slaw, roasted to accentuate the sweetness or sautéed with bacon and chestnuts. The leaves can be removed individually and tossed into a salad or deep fried for an interesting take on a chip. For those who do not like the cabbage-y smell of Brussels sprouts, a quick blanching in boiling salted water can mellow and sweeten the buds, but be careful because overcooking actually accentuates the strong flavor and can leave them with a dull, unappealing color. Chefs learning to properly cook them may be why they are being rightfully accepted as a delicious, healthy vegetable after many years of overcooking.