(Happy Valley, OR)  --  Authorities say a 69-year-old man is in critical condition, after he was set on fire in a Denny's restaurant in Happy Valley.  The Clackamas County Sheriff's Office says a man walked into the restaurant around nine o'clock last night, sat next to the victim, then poured a liquid on him and tossed a burning object at him, setting him ablaze.  The assailant, who's described as being five-feet-ten to six feet, in his mid to late 20s, wearing a flat-brim hat, black hoodie, gray sweatpants with a black stripe, and black shoes, ran out of the building.  Deputies are hoping witnesses will step forward.