MUSIC MATTERS: Despite his bowler hat, fur jacket and grizzly beard, Sean Lennon could not go unnoticed at United Bamboo’s show Saturday. Looking a little Nanook of The North-ish, the musician said the jacket actually belonged to his girlfriend who picked it up at a secondhand store in Iceland. Every year Lennon spends his birthday, which he shares with his father, there. Yoko Ono illuminates a light sculpture she designed for the former Beatle. Their son is still making his own music. His band The Ghost of A Saber Tooth Tiger will release Victorian Cyborg early next year. MGMT and Sonic Boom’s Peter Kemper also caught Saturday’s show, as did architect Vito Aconci and Warus Ahluwalia. Another fan of the designers, Humberto Leon of Opening Ceremony, is cooking up a new gig. This “whole new concept” is geared for the U.S., but that was all he would spill about his plans.