The Telethon event will show up during short periods of time. You could check the countdown in the widget on the left side of the playing screen that will appear some hours before the challenge starts. 

 

This special TV station has a different objective since you won't receive money after each broadcast. Now, you should invest your in-game money wisely to have as many as many phone operators as you can, so they could attend phone calls from your audience. This time, your money will be earned through donations. The more you upgrade your premises and your TV shows, the more operators will work for you. Take care of your staff to optimize your workflow!

 

You will be able to unlock very special star celebrities for your permanent TV stations (also for the incoming ones) depending on your result. They will provide new boosters to your TV shows. Don't worry if you couldn't reach the highest objective, you will be receiving prizes on each milestone!

 

Since the event will provide new boosters each time, the Telethon will restart every week so you could accomplish all the challenges requested.