Of the many elements that go into creating a festive holiday party, penguins are not usually on the short list. But Boston PR guru George Regan does things his own way, and so, along with about 400 human guests, he invited a couple of the flightless birds to his annual Marina Bay bash. Surely the little visitors — from the Mystic Aquarium — made the biggest splash at the event? That’s hard to say, given all the luminaries on the guest list. On hand for the seasonal soiree: presidential candidate and former Governor Bill Weld, House Speaker Robert Deleo, Secretary of the Commonwealth William Galvin, UMass President Marty Meehan, Bank of America Vice Chair Anne Finucane, former Mayor Ray Flynn and his wife, Kathy, Legal Sea Foods CEO Roger Berkowitz, Suffolk Construction’s John Fish, Mystic Aquarium President Steve Coan, Boston Philharmonic Orchestra conductor Ben Zander, and many more.