Soon every gathering was being called an ' - In ' of some kind . Rowan & Martin 's Laugh-In , a television comedy series , began to appear on NBC just a year later , January 22 , 1968 . Soon every gathering was an ' - In ' of some kind : Rowan and Martin 's Laugh-In comedy television show began airing over NBC just a year later , January 22 , 1968 .