Boston Ballet dancer Rachel Cossar (left) mingled with George P. Johnson employees Pam Bittner (center) and Gina Colombo at the opening party for Sip in Downtown Crossing on Monday night. The new restaurant took over the space that had been Bina, just down the street from the Opera House. Also at the party were Sip owners Chris Damian and Brad Dalbeck , of Legendary Restaurant Group, who happily showed off their newest venue to WAAF personality Greg Hill , Peter Christie of the Massachusetts Restaurant Association, and bread guy Joe Piantedosi . . . . In other restaurant news, Marlon Wayans dined at Bricco on Monday night. He said he was there because the restaurant was recommended to him by Adam Sandler.