Moed Katan, Chapter One, Mishnah Seven
This mishnah prohibits marriage during the festival. It seems that the central idea is that one should use the festival to celebrate the festival and not as an opportunity to celebrate something else. The rabbis did not want people to say, Since I cant work on the festival anyway, I might as well use it for a wedding celebration. Rather, both the week of the festival and the week of the wedding celebration should have their own separate times.
1) One may not marry a woman during the festival, whether a virgin or a widow, nor may one perform levirate marriage, because this is a joy for him.
a) But one may remarry his divorced wife.
2) And a woman may make the adornments [for her wedding] during the festival.
a) Rabbi Judah says: she may not put on lime, as that is a [temporary] disfigurement to her.
Section one: As stated in the introduction, one may not get married during a festival. The mishnah emphasizes that this is true even if the woman is a widow, for whom a wedding celebration was not as expansive. It is forbidden even to have levirate marriage with ones dead brothers widow. Even though this was probably not as celebratory occasion as a more typical marriage, it is still a joy and therefore it is prohibited.
There is only one type of marriageremarrying ones divorceewhich one can have on a festival. Since the couple has already been married, this is not as joyous of occasion and therefore it is permitted. This clause sheds some light on the first clause. Marriages are prohibited when they are the first time that a couple will have a chance to be married. It is partly, at least, the anticipation of the new that makes a marriage a joyous occasion and therefore prohibited during the festival. When the novelty is gone, the joy is diminished. [I realize that many will disagree with this assessment, thinking that remarriage is a great joy. While this point is debatable, the rabbis thought otherwise.]
Section two: Although marriage is prohibited on the festival, a woman use that week to make the adornments (the perfumes and makeup) that she will need on her wedding day. Although she is using the festival to prepare for something that she will not need during the festival, since it is not a lot of work she is allowed to do so.
Rabbi Judah places one limitation on this. She cannot put lime on her body to remove hair and to make her skin look better because while the lime is on she is disfigured. Rabbi Judah holds that she should not do anything that will make her look ugly on the festival, even if it is only temporary.