'Forces of Nature'

Now we know what Ben and Sandra did last summer. The two stars tangoed their way through Forces of Nature, a romantic comedy from director Bronwen Hughes (Harriet the Spy), arriving March 19. The film concerns a regular guy (Affleck) and the eccentric woman (Bullock) he meets on his way to the altar. After they've spent most of the flick at each other's throats, a dance brings them together — and allows the stars to display previously undetected fancy footing. ''Ben turned out to be a pretty fine dancer,'' says coproducer Donna Roth, ''but Sandra could be a professional — she's unbelievable.''