Where can I get power-ups?

You can get power-ups as gifts from your Facebook friends via the Mystery Gift. You can send one gift per friend per day.
You can win power-ups from the Daily Spinner.
Power-ups can also be purchased with Bird Coins via the shop. You can find the shopping cart icon from multiple places in the game, i.e. from the bottom of the Tournament screen and from the pause menu. You can also purchase power-ups directly from the power-up menu inside a level if you do not have any of the selected power-up on your account.