So ... to start with the before the Son's of Liberty formed, the British decided to place taxes on tea and basically shipped goods. They felt that they had the "right to pass taxes and laws" but colonists were angered with this and said that "no taxation without representation" What this means is that, since the British did not have any votes in parliament that gave them the right to do so, and the people did not have anyone to represent them. Sound unfair huh?
So now this will answer your question...
The Son's of Liberty were colonists in Boston who opposed this ( what I stated above about tax without representation). Therefore, to show there opposition, they were in disguise as Indians, boarded a ship that was carrying goods, tea to be exact,and dumped and destroyed about 342 crates of tea!
Wowza!
This was known as "The Boston Tea Party Act"
Hope this helped!