The Pnyx is a small rocky hill. It was the meeting place of one of the world’s earliest democratic parliaments where all citizens gathered together and anyone could go to the “stepping stone” (speaker’s platform) and give a speech. If you are persuasive enough they vote for you (by rising hands and shouting:) and later it becomes a law.
Each meeting started with famous “Τίς ἀγορεύειν βούλεται;” which means “Who wishes to speak?”
You can experiment with your friends and practice your public speaking skills imagining yourself one of the members of ancient parliament or just persuade them where to go this evening;)