Sulani Island Festivals - When Do They Happen?

Thanks everyone.....glad to see that they're happening in your games. Perhaps I'm just missing them by not being there at the right location or right time. My Sims live on that 50x50 lot on the island with the 4 lots (forgot its name). @AprilDawn - I totally agree; we do get notifications for anything and everything in the game, it would be nice if we got a notification for festivals too.