I’ll set a topic and everyone gets to make a pertinent comment as though two people were conversing about that topic but can only speak using a title of a song.
If the topic were 'Raining Outside', the first comment from person one could be, “Stormy Weather” to which person two might add “I can see clearly now” followed by number one's “It’s raining men.”
However, if you can’t think of a song title that goes with the theme, start a new one based (sometimes loosely) on the previous comment. Like, “You don’t bring me flowers anymore” The next commenter can add whatever he or she chooses to add to that comment but should try to stay apropos of the topic. Eventually it will devolve into something completely different.
Topic - A Typical Day in Congress
Two politicians meeting in the halls:
Person 1: "Lies" - Knickerbockers
Person 2: "Anyway you want it" - Dave Clark Five
Person 1: "We Didn't Start the Fire" - Billy Joel
Person 2: "Takin' Care of Business" - BTO