Boomerang could be described as a card-drafting game (like 7 Wonders or Sushi Go!) mixed with a roll-and-write game (like Yahtzee or Qwixx).
At the end of each round, players mark different things off on their score sheets, corresponding to what they earned from the cards they selected. Players earn points for seeing sights, collecting Australiana, seeing animals, and so on. After five rounds, the player with the most points wins.