Original: 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.
Simplified: 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.