Who? The British needed to calm the colonists after the Boston Massacre. So they took away all taxes, all except one that is, they kept the tax on tea!
What? Tea was the colonists favorite drink, their faces were filled with rage. They knew they were going to get revenge soon. And it is NOT going to be pretty. (For the tea at least.)
Why? The colonists did THIS act because they weren't going to have to pay a tax for their favorite drink. So they got in 3 ships nearby and dumped quite a lot of tea in the harbor.