Keturah - a type of melakhah that needs definition and application. Specifically, fire and incense. Plus, R. Elazar's leniencies vs. the sages. And the politics of leadership and wealth. Plus a new read of the Mishnah, in the light of the principle that "silence is an endorsement." Plus, the impurity of a 3-part pepper mill. Also, a child's wagon can be rendered impure. Plus, whether that wagon can be dragged in the ground - will it make a furrow and count as plowing? Or is it acceptable, given the lack of intent? (Depending on whom you ask) R. Yehudah contradicts himself, so the Gemara resolves the contradiction.