“Free time” was actually quite available throughout the year. First consider the number of holidays scattered across the year: no work on every Sunday, every major feast day and the days surrounding it (Christmas, Easter, the Ascension, the Assumption, the Purification, etc. etc.), every feast of a major saint (so 6 or so associated with the Blessed Virgin, St. John the Baptist—associated with the summer solstice or midsummer, i.e., today!, St. Peter and St. Paul, etc.), the feast day of the patron saint of your parish church, of you guild, etc. Estimates vary with region and era, but typically there were around 80-100 holidays spread across the year—more time than we now enjoy. [Here’s an intelligent online summary] (http://www.traditioninaction.org/History/A_021_Festivals.htm)

As for what people did with free time, they did everything we do minus electricity and natural gas, from work to play. There’s no traditional game (i.e., chess, backgammon, cards) or traditional sport (football/soccer, bat and ball games, golf, wrestling, etc.) that they didn’t play. Minus TV and radio, there was lots of story-telling, dancing, and—at festivals—drinking.

As for other uses of idle time, remember that the Middle Ages was a pre-industrial culture; pretty much anything you needed had to be made by hand, esp. if you were a peasant, which about 90% of the people were. In iron-poor areas, even agricultural tools had to be made from wood unless you had enough (or pooled enough) money to purchase, say, an iron plowshare, which would likely be used communally. So a lot of down time had to be devoted to hand-making things: women spun wool/linen, wove it into cloth, and sewed clothes; men carved rake heads and tines, or flails, or made rope and nets, and carved kitchen bowls, etc.

Even in winter, there was still plenty to do. Tools needed to be repaired, wood gathered, water drawn, fields, cleared and prepared for spring planting (or planted in autumn for winter wheat), animals tended, children cared for, stews made, clothes washed, etc.

(Note that I’m focusing on the medieval peasant classes here. With the growth of towns by the 14th century, there was a whole new class of townspeople who had other tasks during their down time.)

Source: General knowledge for this medievalist, but also see Ronald Hutton’s The Stations of the Sun: A History of the Ritual Year in Britain (1996) for the cycle of the year and Judith Bennet’s A Medieval Life: Cecilia Pennifader of Brigstock, c. 1295-1344 (1998), which is a short and excellent survey of peasant life and leisure.

EDIT: My first gold! Thanks for your generosity, o anonymous gold-giver.

Unless they were nobility of some sort, most people in the Middle Ages did not have 'free time', as we might perceive it today.

The average working person would spend the entire day, from sunrise to sunset, working at whatever their designated job was, whether that be in the fields, in an artisans' hovel, or an apprentice to some practical craft. Most people did not do anything after sundown, but those that did would often go to taverns and brothels for some brief enjoyment.

The most free-time peasantry would have would come in the form of religious events. In the Middle Ages, religious pomp and circumstance took a lot of time, with merriment from holidays taking days, and even weeks out of work. These festivals would involve parades, street artist acts, and, of course, feasts.

Now, if the person was of noble birth, they would have nothing but free time. Nobles would spend their free time on hunting, fowling, and playing games like Chess and Duodecim Scripta/Backgammon. Noble women would spend their free time socializing with other women, making small crafts, or horseback riding.

Source: Daily Life in the Middle Ages, by Paul B. Newman, ISBN: 978-0786408979

If you are interested in this topic, I highly encourage you to read Barbara Tuckman's A Distant Mirror

I picked up the book as Dan Carlin had used it as a reference for a couple episodes. It is a fantastic book. It does not cover the "average" person, but I believe an extensive explanation in the beginning covers why exactly Barbara chooses the French noble that she does. Following her subject about, Enguerrand de Coucy, she has so much detail at her disposal that you will get a very thorough description of the times, both at the grand scale and of the everyday humdrum.

Just as a PSA: For those interested in medieval life, especially peasant life, two of the best museums you can visit are the Museum of the Romanian Peasant and the Village Museum in Bucharest, Romania. The Peasant Museum has a large collection of textiles and household items related to peasant life. In particular, the embroidery work on the clothing gives one an excellent idea of the kind of activity that the women would have done in the long winter months.

The Village Museum (Dimitrie Gusti National Village Museum) is an open air museum which contains houses and other structures (mills, etc) from villages. Although these are not necessarily "medieval", you will find that little changed in village life prior to the 20th century (and having visited some Romanian villages, one might argue prior to the 21st!).