New Yorkers owe Charlotte Ronson and Chrissie Miller a debt of gratitude: The two designers scheduled their Summer Lovin' party at Blue & Cream for yesterday evening, and lo and behold, yesterday morning, summer finally obliged. Emboldened by the suddenly seasonable weather, partygoers lined up by the two Mister Softee trucks commandeered for the event, and, treats in hand, stuck to the streets outside the shop to swap licks. "We wanted there to be a nice street-fair atmosphere," explained Miller, Ronson's longtime pal and the designer of Sophomore. "Like, we were planning a kind of miniature bike rally, too, but then it would probably rain, so we dropped it. Another time…" According to Ronson, a nail art stand had been planned and scrapped as well. "The airbrushing lady flaked at the last minute," Ronson explained, showing off her own neon, leopard-spotted fingertips. "Which is kind of a bummer, but at least we got the sun to come out."