Overview:Jack Docherty brings together a jam-packed cast of comedians, actors and famous faces for a riotous celebration of Scotland's most valuable export – its sense of humour. Scotland is a small nation with a big funny bone. It's known the world over for self-deprecation, quick-witted patter and deadpan asides. But what makes it so funny? To find out the answer, this programme delves deep into the BBC Scotland archives to find a century’s worth of classic characters, catchphrases and comedy clips.