When a strange man phoned Stephen Waters '85 last Thursday and invited him to a celebration in his own honor. Waters was understandably suspicious. Waters listened on, and was told that the Coop, in commemoration of its 100th anniversary, planned to honor him, its 100,000th member, in festivities this weekend.

At first Waters told no one but his roommate. "If this is a hoax and it's one of my un-friends, I'll be really embarrassed," he says he thought at the time.

But it was no hoax, as Waters found out when he showed up at the Coop last Friday, where a group of Coop representatives told him he would receive an engraved Harvard chair, a new suit, and some surprise gifts including, possibly, a date with Miss U.S.A. 1982.

Officials at the Coop have known since September that Waters was their 100,000th member, Kathy S. Whittemore, director of advertising and sales promotion, said yesterday, but they waited until last week to inform him so that the celebration will coincide with the 100th anniversary festivities this weekend.

The Coop celebration will take place at noon on Saturday and will include a drawing for a $100 gift certificate.

Waters, who said friends had to persuade him to join the Coop in the first place, described himself as basically a lucky person, saying that over the years he has frequently won raffles and other small contexts. "I just hope I do as well in the housing lottery," he added.