A few years ago I participated in a Purim Se'udah (feast) at which rounds of humorous poetry were written and then recited in a sing-song chant. I believe they're called Grammen.
It was fun, and the tune rang familiar to me, but it was something I had never done before.
1. What is a Grammen?
2. What are its cultural and etymological origins?
3. When/how did it become a part of (some people's) Purim tradition?