Even though I have left the building...er.... country, I'm still voting for a glass or three of rei-shu (cold sake) and somen.
Those very thin, white, Japanese wheat noodles are usually served cold, with a light flavoured, clear, dipping broth (tsuyu). The broth is for dipping, not pouring over the noodles. The flavour of the sauce is from dried bonito fish flakes (katsuo-bushi) with additional nuances from leek, ginger, or myoga. The 'coolest' way to eat somen is chilled with ice.
Some restaurants in Kyoto serve 'flowing somen' (nagashi somen) in the summer; the noodles are placed in a hollow bamboo gutter across the restaurant, which carries ice-cold water. As the somen come down the flume and pass by, you pick them out with your chopsticks and then dip them in a container of tsuyu. Catching the noodles requires a fair amount of skill (young grasshopper). As the noodles that escape to the end, usually are uneaten, the diners are under pressure to catch as much as they can. One or two luxurious establishments put their somen in real streams and build decks for the Summer.
Ice-cold dai-gin-jou grade sake completes the cooling effect!