I wonder if I may extend the question to include the illegal side. What tricks did peasants use to cheat their masters? To what extent did they participate in organised groups, such as black markets or smugglers? Any guerilla tactics? That sort of thing.

And what happened to those who got caught?

The period /u/Aclockworkwalrus selected is more or less bracketed by two of the biggest and most brutally suppressed violent revolts, the (English) Peasants' Revolt of 1381 and the (German) Peasants' War of 1524-25. And there were plenty of other major--and much more infamous than the 1381 revolt at the time--and minor uprisings throughout the period. Heck, in 14-15th century Italy, one gets the impression that violent revolts by the villages outside major cities as well as urban residents were just another Sunday afternoon excusion.

But most of the violence was spontaneous and thus urban--a flashpoint event or frustrated speaker igniting something in the audience. One case that caught the attention of western Europe more broadly occurred during the pope's ill-fated stay at his Viterbo palace in 1367, where he was meeting with ambassadors from other Italian and French cities. The butler (essentially) to the bishop of Carcassonne decided it was a grand idea to give the bishop's poodle a bath--in the fountain that the city's poorer residents used for their drinking water. A servant woman observed the tainting of their water supply and tried to raise the alarm, and the butler killed her on the spot. This being 14th century Italy, basically all of Viterbo turned into a giant bloodbath, the palace was stormed, ambassadors slaughtered.

For sustained revolts, moreover, scholars have questioned the extent and nature of "peasant" status among leaders, generally uncovering evidence that the leaders had significant money or education ("peasant" could mean a range of economic statuses), or frequently, were actually city-based. That doesn't mean there weren't violent (against people or things) uprisings in the countryside, like when the peasants of St. Albans priory's landholdings in England stormed and vandalized the monastery.

But rural peasants did have, and use, political or legal appeals. They petitioned for everything from a better-qualified (more educated) preacher to give better sermons, in 15C Germany; to releasing a single village man from jail (15C France); to the restoration of fishing rights in a local stream (14C England, 15C Germany); to hey, stop raiding our village and burning our fields (everywhere). They petitioned their local manorial court or canon (Church) court, or the council of the nearby town. In some cases they appealed to the regional duke. There are even cases of delivering requests and petitions to the relevant king or to the pope!

In general, these petitions seem more often to have been collective rather than individual, such as a family or a village uniting with one request. Women as well as men could be primary parties to these suits (even though, increasingly, normative laws tried to restrict women's ability to represent themselves/sue in court). In Chalons-en-Champagne in 1418, "the wife and close friends of Regnault le Moqueur, a poor man, manual worker, and labourer in the vineyards," petitioned the duke to release Regnault, who was charged with a long and colorful history of ranting and raving in public and plotting the general overthrow of the government (but never succeeding in initiating action beyond, apparently, a long string of robberies that he had been pardoned for). Regnault's nameless wife is not just a party, but the first listed party to the suit.

Women unquestionably participated in violent uprisings, but in general, chroniclers limit or wash over their role. The German Peasants' War has a few exceptions, but there are some differences in how collective action is depicted in that particular time frame related to Reformation polemic.

Additionally, there are some one-off cases of collective protest that etch a civil disobedience line between violent uprising and staid petition, although these were more typically urban. At a church in France's Languedoc region in 1378, a spontaneous prayer session/tax protest erupted during Mass one day, when the traditional unveiling of a Virgin Mary statue during the service prompted the gathered townspeople to start imploring her for mercy from the recently imposed tax burden. In 1347 Naples, a parade of children launched a war protest of sorts (trouble with Sicily), gathering before the palace waving banners and shouting Pace, pace.

And finally, there are cases that aren't outright protests against the lord/abbot/council, but historians have nevertheless connected to dissatisfaction with political or economic circumstances. The turn towards "heresy"--a religious-oriented movement that the Church perceived as a political-theological threat to its power--created some of the biggest and thorniest problems in the high and later Middle Ages. The German Peasants' War in particular is the historiographical site of a major, generations-spanning scholarly battle over the role of religion, economics, and social class in triggering peasants and burgers to take up arms. The other major category is deflecting anger at the government onto anger at a persecuted minority group of choice--Jews especially, but lepers, prostitutes, and Muslims have all also been studied as targets for often extreme violence in lieu of going after the joint oppressor.

If you're interested in reading more, I highly recommend picking up Samuel Cohn's Popular Protest in Late Medieval Europe. It's an anthology of primary sources in translation from France, Italy, and the Low Countries, mostly but not entirely 14th century. You can really see that even contemporary, hostile accounts recognized the sophistication of peasant/burger complaints and goals--that peasants had come to understand even local concerns over taxes or unbridled arson in terms of larger political issues of power, law, and justice.