I've begun emailing people little notes on the daf, based on things that come to mind as I deliver the daf shiur here in Allentown, PA.
Here are digests of those emails. Unlike the standard daf sites, I'm not really touching these up to make them into full divrei torah; these are more like jumping-off points for people who want to look into issues a little further, but the reader will have to do most of the work.
19a - "safek mashkin."
Several "Rashi" notes in Nedarim give away the fact that the author is not really Rashi. One of those is on "safek mashkin" - contrast the Rashi on Nedarim 19a with his comment at the top of Pesachim 16a on "safek mashkin" and you'll see what I mean.
The gemara at the bottom of 25a discusses the exaggeration of a snake that is "like the board in an olive press," and it compares this to a story about a snake so big that it swallowed 13 crates of straw.
The funny part in this is that the straw story may, itself, be an exaggeration! See Rashi Shabbos 119a "Treisar" and Tosafos Bava Basra 133b "Ilisa", both of which show cases in which 12 and 13 are used in exaggerations...
Make sure you see the Ran on dina d'malchuta (the law of the land) on 28a. There are many fews of how 'dina d'malchuta' works. Here are some:
1. One view is that the king owns the land. Rashba, like the Ran, takes this view. Radvaz also took this view, although he said it was specifically a result of the king having conquered the land.
2. A second view is that it's a function of the nation itself. The Nimukei Yosef on our Nedarim daf points out that we say "dina d'malchuta," the law of the kingdom, not "dina d'malka," the law of the king. The Beit Yosef, in his teshuvot (Avkat Rochel), presented this view. Some, like the Rama (in a teshuvah) and Rashba (also in a teshuvah), say this is meant to empower the king to help the nation. Rav Moshe Feinstein appears to have held otherwise, as he limits government authority to areas that directly affect the government itself.
3. A third view is that HaShem gives this right to all kings, based on Sanhedrin 20b on the rights of Jewish kings. Of particular note is the Meiri to Bava Kama 113b.
4. A fourth view is that since HaShem required bnei Noach to create courts, those courts (and related governments) must have legal standing.
5. A fifth view is that the power of government is actually a function of communal custom. The Rosh to Gittin 1:10 seems to follow this, and Rav Moshe used this in discussing labor laws. Rashba also seems to support it.
1. 31a - Regarding the issue of a seller being sad, or feeling he has come out the "loser," in a sale, see Berachos 5a regarding HaShem's disposition upon giving the Jews the Torah. The general trend in the Gemara is to view a seller as unhappily liquidating an asset, even if the seller is a merchant who does this for a living.
Regarding the delay of the Bris Milah for Moshe's son Gershom, the Chasam Sofer to Shabbos, 131a or so as I recall, where he presents two fascinating rationales for why Moshe delayed the bris. One has to do with the preference for a metal blade, the other with the geographic placement of Yisro's home, the inn and Egypt.
Just a quick note on 32b (although there is much to say about the bottom of 32a, on drafting talmidei chachamim for war!) - Malki Tzedek is criticized for blessing Avraham before blessing HaShem. Therefore, it is appropriate to be careful when making a "L'Chaim" that we first make the berachah on the beverage, then take a drink, and only afterward say "L'Chaim."