Brooklyn design duo Nicholas Andersen and Julie Ho’s Confettisystem decorations have been featured at Karen O’s birthday party and sold at Maryam Naser Zadeh, Opening Ceremony, and Bergdorf Goodman. Now they can swing from your ceiling, too; the pair has teamed with Urban Outfitters to launch an affordable collection of ornaments ($12) and party hats ($10), plus other fiesta accoutrements, ebulliently titled Partyparty (526 Sixth Ave., at 14th St.; 646-638-1646). These disco-ball piñatas ($30 to $48) will add some sparkly nondenominational cheer to any end-of-year happening. For more festive holiday-shopping ideas, click here.