1) The Rabbis enacted this prohibition due to a concern that one might inadvertently smooth out a section of ground to play on by filling in holes. Doing so would constitute a violation of the prohibition called ''Choresh'' - ''ploughing'' - if it was outdoors, or ''Boneh'' - ''Building'' - if it was performed on indoor dirt floors. The Rabbis prohibited playing even on paved outdoor ground, so that one wouldn't end up playing on unpaved ground. Both playing marbles and soccer outdoors would be included in this prohibition (See Mishna Berurah 308:158). 2) This principle is mainly applied to Rabbinical laws.

1) The problem with folding, according to most authorities, is that it improves the look of the garment by smoothing out the creases. Effecting a significant improvement to any object is called ''Tikkun Keli'', and is forbidden on Shabbat. The only time that folding on Shabbat would be permitted, is if the following criteria are met (See Shulchan Aruch 302:3): a) The garment will be needed sometime during that Shabbat; b) There is no other garment available that would be suitable for Shabbat; c) It's a type of garment that doesn't crease easily, and upon which creases cannot be seen so clearly (with this type of garment, folding doesn't effect a significant improvement); d) The act of folding is performed by one person. The above criteria apply to folding on the original folds. If, however, one isn't folding on the originial folds, it's permitted even without the above criteria. The Mishna Berurah 302:19 writes that those who wish to be stringent on themselves, and not fold things at all (that is, even not on the original folds), are acting in the most preferable way. There are many people nowadays who do fold things (like a Tallit) on Shabbat. The Aruch Hashulchan (302:12) writes that these people are relying on the opinion that the Sages only prohibited the type of folding that people performed in their day, that is, where people were very careful to fold in professional manner which effectively smoothed out the creases.

בענין קיפול בגדים יש הרבה חילוקי דינים ואין לקפל שום בגד

1) It's forbidden to put out a fire on Shabbat. One of the verses from which Shabbat prohibitions are derived states: ''You shall not PERFORM any forbidden labor...'' From the word ''perform'', the Talmud (Shabbat 120) also derives that only direct performance of forbidden labor is Biblically prohibited, but not indirectly causing the forbidden activity to take place (which is termed ''Grama''). Therefore, the Talmud states that, although it's prohibited to throw water directly onto a fire, one may place barrels of water in the path of a fire, so that when the fire reaches the barrels, they will split open and the water will extinguish the fire. There are three opinions among the early authorities (Rishonim), as to how to apply the case of the barrels to our case of pouring liquid onto a garment: a) There are those who rule that the Sages only permitted indirectly putting out a fire in cases similar to the barrel case, where there is a something between the water and the fire (that is, the walls of the barrel). Making a garment visibly wet in order to put out a fire, closely resembles direct extinguishing, and is therefore prohibited; b) Simply soaking a garment on Shabbat with clean water (or another liquid that cleans) is a violation of the prohibition against ''Laundering''. Therefore, there are those who rule in our case that, although, in contrast to opinion (a) above, placing liquid on a garment is a permissible way of indirectly extinguishing a fire, one cannot violate the prohibition of ''Laundering'' in the process; therefore, only liquids which would not clean the garment can be used; c) There are those who rule that placing clean water on a garment is only prohibited if the garment itself is dirty. Therefore, if the garment that catches fire is clean, one may even place clean water on its edges in order to indirectly extinguish the fire. Based on the Shulchan Aruch 334:24 one should conduct oneself in accordance with opinion (b) above. Of course, all of the above is only dealing with situations in which there is no danger to humans. In situations where there is any danger to human life, one may do anything to put out the fire as quickly as possible.