Beitzah 9: When the Sages Get It Wrong (according to themselves)

Carrying a ladder on yom tov - muktzah? Not muktzah? To what degree? An apparently straightforward machloket. The Gemara makes it clear that there are other issues as well - including others' perceptions (mar'it ayin), which leads to discussion of other cases of mar'it ayin. Also, the story of R. Hiya's sons, and their misinterpretation of the Mishnah.