The play's the thing in this once-over-lightly exercise--namely: a $25,000 prize for the equity portfolio that performs best during any one of a series of nine 26-week holding periods between April 1, 1985 and July 1, 1986. Not too surprisingly, entrants must make their stock picks from a ""hot list"" compiled by the author. The Weiss register encompasses 200 predominantly speculative NYSE issues running from Advest Group (a regional brokerage firm) through Zapata Corp. (an oilfield-services concern with a sizable stake in offshore drilling). Well over half the text is devoted to breezy, smart-alecky, sometimes tasteless capsule reviews of the selections. (Deere, the world's largest producer of farm machinery, ""was lucky not to have been plowed under"" by agribusiness hard times; declining battery sales are characterized as the least of Union Carbide's foreign worries ""in light of the recent poison gas release at a factory in India. . ."") There's little to be lost in playing Weiss's game--for fun. But newcomers should be wary: the brief advisories tend to accentuate the positive aspects of dubious enterprises and strategems.