Aziz Ansari played a practical joke on an unwitting guest at Montauk hot spot Ruschmeyer’s over the weekend. The “Parks and Recreation” star managed to convince a poor schnook in the men’s room he was about to relieve himself into a sink. “The urinals do actually look like sinks,” explained a spy. “One guy in the bathroom wasn’t sure, and when he went to go, Aziz yelled, ‘You can’t go there, bro!’ ” After the admonishment, “The guy looked scared for a minute, then realized it was a joke and people were laughing at him.” Also Sunday, Beastie Boy Mike D co-hosted the Rockaway Plate Lunch Truck Yard Party for Sandy relief, and jumped in a dunk tank to raise funds. Guests included Kelly Bensimon.