The Carousel is a very unique attraction. When you start a character, this attraction is the very first ride you'll have. Also, through the end of January 2013, Flo from Progressive comes in and upgrade it and makes it the Flogressive Carousel. When you want another you can go to the shop and click on attractions, then click on the first attraction which would say "Carousel". It might take 3 energies to build it completely, but at the last step, you will need 50 coins, 20 goods, and 25 thrill points. Than your set.
If you take a close look at the happy customers they look like people from Empires and Allies or CityVille 1. If you want to upgrade the Carousel to level 2, it's really simple, all it takes is 13 coins and 10 goods, which you would probably already have, also you will need to do this task later on in the game. Once you boost it, (for level 1 Carousel) you can get 20 Thrill Points. This attraction will help your popularity slightly because it's a beginner