We do not ride on an animal (and see above, Chapter 305 Paragraph 18, for the laws of a carrage)
We do not swim in water, even in a pool in the yard, because the water can overflow and thus resemble a river. If there is a barrier around the pool, it is permitted, because even if the water overflows, the barrier forces it back, so it is more like a container, and there is no reason to decree out of concern that one will make a float.
We do not clap nor to we slap our hand to our thighs nor do we dance. This is a rabbinic decree lest one come to fix a musical instrument. It is even forbidden to tap one's fingers on the ground or the board or to each other as singers do, or to shake a nut for a child or to play with two nuts so that the child will be quiet. All of this and anything similar is forbidden, based on a rabbinic decree preventing the fixing of a musical instrument. Clapping using the back of the hand is allowed. Rem"a: Today people clap and dance and we do not stop them because it is better that they sin unintentionally . . . There are those who say that today, everything is permitted because we are not proficient in the fixing of instruments, so there is no reason to make decrees preventing the fixing of instruments, as this skill is not pervasive. It is possible that based on this, the practice has emerged to be lenient (Tosafot at the beginning of Perek HaMevi Kadei Yayin).
We do not hold court. Rem"a: Therefore, it was forbidden to arrest and imprison someone who deserved a punishment in order that he not escape. All the more so is it forbidden to give him lashings, because this is a legal matter. If he escapes, we are not liable (Beit Yosef Chapter 253 in the name of the Shibbolei haLeket). We do not betroth women. Rem"a: There are some who allow betrothing when the man has no wife and children (Rabbeinu Tam), and it is possible that this also the rule with regards to a wedding (Sma"g). Even though our established practice is not like this opinion, we can rely on it in a pressing situation, for the additional reason that human dignity is important. It often happens that they do not work out the dowry on Friday until nightfall, and in that case they do the betrothing and wedding on Friday night, because they already have the wedding meal ready and it would be embarrassing for the bridge and groom to not marry then. In any event, a priori one should be careful that it not come to this (and see Tur Even HaEzer Chapter 63). And we do not do chalitza nor we do yibum [levirate marriage], nor do we have a wedding, nor do we dedicate objects to the temple, nor do we dedicate the value of a person or an animal to the Temple, nor do we renounce private use of an object, nor do we separate trumot or maasrot, nor do we redeem a firstborn son [[[wikipedia:pidyon haben|pidyon haben]]], nor do we divorce unless he is very ill (the world is weighing heavily on him). For all of these things, if they were done, whether by mistake, on purpose, or erroneously, what was done is regarded has having been [legally] done.
Someone marrying a widow should not have sex for the first time with her on Shabbat or a holiday (and see above chapter 280).
It is forbidden for a person to float something in water away or towards him. Therefore, it is forbidden to divide woodchips in the water in order to make the water cleaner.
If a boat is sitting on the sand underwater and is not floating at all, one is permitted to enter it. If it is attached like boats in a harbor, even though it floats, one is permitted to enter it.