Well I knew water melon was a super-food, but I didn't realise it was quite as versatile as this! Indeed, it's multi-functionality prevails throughout much of this bizarre hybrid of comedy, musical and straightforward porn. It's all set in a Taiwan where it hasn't rained for ages and where these fruit are in short supply. That's where we meet two people who live in the same block of flats. "Hsiao-Kang" (Kang-sheng…