NOBODY needs an excuse for a party in Hong Kong - even if it's in the middle of the day. So yesterday, Keeping Posted joined the good, the great and the social illuminati at the big top set up on the stage of the Lyric Theatre to enjoy all the fun of the circus, sawdust and all - although none of us, apart from a few clowns, were really dressed for the ringside frolics. The novel occasion was the brainchild of James Cundall, managing director of Lunchbox Theatrical Productions to announce Barnum - The Greatest Show on Earth which his company will launch in Hong Kong on November 30 for a 16-show run. With one of Britain's top stage stars, Paul Nicholas, in the lead, the musical will kick-off with a glittering gala night in aid of children's charities. But why stay with one superlative when a few more would do. ''So welcome to the 'greatest lunch in town' for the 'greatest presentation ever held','' Cundall rattled on. It took time for everyone to soak in the circus atmosphere (described by one guest as the smell of the crowd and the roar of the greasepaint!). But before long, the guests were lining up by the stalls trying their hands at the various games. ''Look, I managed to knock down five tins with one shot. And that's supposed to be unusual,'' said a delighted Diane Butler, cuddling the furry raccoon she won for her efforts. On the next stall, Omni Hong Kong Hotel general manager John Girard, who was making a right pig's ear of obtaining his own furry raccoon, could only look on in envy. Writer Sandy Butchkiss had intended only ''to peep my little nose in and then leave''. Two hours later she was still there, her nose peeping into a glass of wine. While the likes of glam entrepreneur Nancy Jong, Justice Ross Penlington, barrister Gilbert Rodway and jeweller Daniel Zigal and wife Suzanne were enjoying the fun of the fair, others were more circumspect about their presence. One guest pleaded: ''Please don't mention my name or I'll get the sack. I'm supposed to be working.'' (. . . we are more than happy to accede to Benny Chan's request.) Legislative Councillor Man Sai-cheong was also there, ready, as he put it, ''to do his bit for the arts''. As Mr Man, a keen supporter of the local cultural scene, savoured the circus atmosphere, I asked him if it reminded him of the Legco chamber. ''We are here to have fun - not for the truth,'' he emphatically replied.