In the two-plus years since the first Playboy Club bounded boldly onto the entertainment scene in Chicago, 24 of this magazine's prettiest Playmates have taken the bountiful Bunny trail to fun, travel and excitement as highly paid hostesses in our ever-lengthening chain of luxurious key clubs. With this issue we present a neat twist on the customary Playmate-to-Bunny progression: she's ingenuous Jan Roberts -- the first (but undoubtedly not the last) Playmate to be discovered among the hutch honeys already decorating club premises. Like hundreds of beauties from every part of the U.S. and several foreign countries, Brooklyn-born, Toledo-bred Jan stormed Chicago specifically in hopes of landing a job at the Playboy Club. Her credentials (executive girl Friday for the Juhl Advertising Agency of Elkhart, Indiana, and honor graduate of a two-year medical technology course in the same city) were impressive enough to earn her a Bunny berth. Although the lissome (39-23-35) arrangement of her 120 compact pounds on a five-foot-five frame tends to belie it, Miss August prefers mental exercise to physical; she thrives on chess and bridge bouts, reads omnivorously (mostly books on mathematics and theology), dabbles in graphology, and earnestly paints landscapes which bear, she believes, "an unfortunate resemblance to my favorite foods -- spaghetti and cheese blintzes." She can't abide a sloppy pad, views beatniks with suspicious brown eyes, loves shoot-'em-up war flicks, feminine frills and Louis XVI antiques. Affectionate by nature, she is apt to greet friends with warm hugs and double-cheek kisses. Jan regards her current welcome-to-the-club duties with honest satisfaction. "I'm interested in a show business career," she says. "As a Bunny, I'm already leading a show biz kind of life. It's a big step on the way up." For a fetching view of rising and shining Jan, consult the foldout where our breakfasting Bunny-Playmate is shown starting her day -- and brightening ours -- with an r.s.v.p. smile.