Megillah 5a-6a (from last week):
Psst! I heard a rumor that Rebbi was planting on Purim, and bathed on 17 Tammuz, and tried to get rid of Tisha B'Av!
Oh come on, he wasn't trying to get rid of Tisha B'Av forever. It's just that Tisha B'Av fell on Shabbat that year, so they delayed it to Sunday, so Rebbi said "Since we're delaying it anyway, why not just skip it?" The sages were not amused.
Bathing on 17 Tammuz isn't really a problem anyway -- only eating and drinking are.
But how did he plant on Purim???
This question is debated at length. Purim is called "yom tov" (Esther 9:19), so work is forbidden. Ok, Rav was a 14 Adar kind of guy and was planting on 15 Adar. But wait, he was from Tiberias, which was walled at the time of Joshua, so his Purim is on 15 Adar! Ok, then he was planting on 14 Adar.
But is it so obvious that Tiberias was walled at the time of Joshua? Chizkiyah (presumably not the king) read megillah there on both the 14th and the 15th, out of sheer confusion!
In the end, the resolution is that fasting and public mourning are banned on both the 14th and 15th (for everyone), but work is only banned for at most one day, and it's only banned in places that have the custom of refraining from work on Purim. This is because the people accepted the bans on fasting and mourning, but never accepted the ban on working. See page 8 of this document on "Seudat Purim on Friday Afternoon" for discussion of this controversy. This document suggests that Rebbi represented one side in the debate over whether working is allowed on Purim. The Talmud would rather harmonize this and suggest that Rebbi wasn't doing anything wrong, just following the custom of his place. Or it could be that it didn't count as really "working", since it was a happy kind of work. We don't know what Rebbi would have made of this parallel, but this has some things in common with the contemporary suggestion that people who are in white-collar jobs during the week may find it restful to do manual labor on Shabbat, as the nature of "work" has changed.
Whoa!!! Hold on a second! ("Gufa") They didn't know whether Tiberias was walled at the time of Joshua? Of course it was! We know from Joshua 19:35 that Rakat was walled at the time of Joshua, and Rakat is Tiberias. But the problem is that it is only walled on three sides, and the fourth side is water. This makes it clearly unwalled for the purpose of jubilee redistribution (since the requirement there is chomah, wall, from Leviticus 25:29, and Tiberias doesn't have a wall all the way around). But the requirement for Purim is just that it is not perazi (unwalled), from Esther 9:19. If that means that it's not exposed, Tiberias is exposed. But if that means that it's defended, Tiberias is defended. Hence the ambiguity!
Next we get into lots of fake etymologies for names of cities. Tiberias wasn't named after the emperor Tiberius; Teverya is from "tovah re'iyatah" (its appearance is good). Ok, most of these are lost in translation. But when EAKO spent a year in Saratov, she traced the name to "sur meira' va'aseh tov" (Psalm 34:15). Anyway, I don't think the rabbis were under any illusions when they made up these etymologies. They weren't linguistic ignorami; they were affirming the Jewish character of the land of Israel in the face of many conquests.
Did you ever wonder what was really going on with Zebulun and Naphtali in Judges 5:18? Zebulun complained to God that Naphtali et al. got fields and all sorts of useful things in their tribal allotments, while Zebulun was stuck with mountains and water. God responded "Don't worry, you got the chilazon!" It's the snail that produces the blue dye techeilet. Snails!