Note that this is not a day log
This was one of the worst practical jokes I've ever heard about. It was shortly after the Soviet collapse and Estonian (re)independence. Estonia had introduced the national currency, krona. Keep in mind that it was very unstable times.
One of the most popular tv-comedies in Estonia was interrupted by an official announcement. A gloomy looking guy in a suit appears in a telly and addresses the Estonian people that the national currency will be worthless tomorrow.
The banks were already close for the day but no doubt the whole nation goes crazy. And all aye, this was only part of the tv-comedy but the damage was done!