Bruno Mars and Nick Jonas, who ended his run in Broadway’s “How To Succeed in Business Without Really Trying” last weekend, took to the stage to sing after dining at the Darby on Saturday night. They dined separately with friends before taking the stage for back-to-back performances. Mars sang his hit “Grenade” while Jonas followed with the Stevie Wonder classic “Superstition.” Both received standing ovations. Mars and friends feasted on seafood and red wine.