Behind the walls of one Pittsburgh family's house lurked a menace that was a fixture in their home for 13 years: an alarm clock. Every night, Sylvia and Jerry Lynn heard the clock, which went off at exactly 7:50 p.m. After more than a decade inside the walls, it was recently removed by a local air conditioning company. For years, they never felt the need to remove it because Jerry said: "It makes a great conversation piece, particularly with new people."