If you are out on the town one day -- anywhere from Tokyo to Tijuana -- and you suddenly spot a group of animated, middle-aged women all wearing red hats and purple dresses, don't be puzzled. Smile! You might anyway, because it is an oddly heartwarming spectacle when a chapter of the global sisterhood known as the Red Hat Society goes out in public. Oh, and it's all right to gawk: Ladies in red hats are clearly not averse to attention.

The seed of this eccentric organization -- which actually calls itself a "disorganization," since it has no rules or bylaws -- was sown in California in 1997, when a woman named Sue Ellen Cooper gave a friend who was turning 55 two gifts: a copy of the poem "Warning," by the British writer Jenny Joseph, and a bright red vintage fedora.

Why a red fedora? Because the poem, a wryly welcoming nod to looming old age, begins this way: