Celebrity tends to make some people forget how old they are. Take Kirstie Alley of "Cheers." She lists her age as 36, but USA Weekend magazine did some checking and found that her high school in Kansas City lists her birthday as Jan. 12, 1951, which means she's 40. Arsenio Hall also may be shaving years. A spokeswoman for the talk-show host insists Hall was born in 1959, but records at Ohio University show he was born Feb. 12, 1956.