Schach - what can be used for it: the specific examples of the leavings from the threshing floor and the winepress, as delineated and derived from the biblical verses. But not the grain or the grapes themselves, as food can be rendered impure. The Gemara also discusses whether wine can be used for schach, and, interestingly, the fact that it is liquid is not a concern. Plus, another sukkah connection to Nechemiah. Also, bundles are not acceptable for schach, but unbundled should be fine. The storehouse isn't acceptable as a sukkah either... Note the need to do some active preparation that makes a sukkah a sukkah. [What's What: Ta'aseh, ve-lo min ha-asui.] Plus, the possibility of using arrow shafts for schach. Or wormwood leaves or licorice leaves (the former of which gets nixed).