There are a variety of things to do on a ship: work shifts, sleeping, having meals, and the basic downtime activities of reading, listening to music, gossiping, and so forth. To deal with periods of inactivity that can last weeks or months, there are various activities that crews can indulge in to pass the time and keep their morale and sanity.
1. Movie Night
Often cut off from timely access to media and entertainment offerings, most ships will have some sort of 'Movie Night' where the communications crew will have by some means gained access to the latest movies. For most non-corporate owned ships this involves illegally downloading movies and events that are still in theaters. The most common application of this is tearing down the tables and chairs in the mess area to make it a makeshift theater space. On larger government and corporate ships it is more likely to have licensed showings of new films and media.
On more piratical ships screenings of pornography, snuff films, and other black feed offerings are as common as pirated films.
2. Themed Dinners
While things like Taco Tuesday and Meatloaf Mondays might seem trite or cliche to the average person, but for a person on a ship, far from home and the routine things like the change of day and night, having something like an anchoring meal. Rather than just a basic meal, many ships will make the meal a weekly event, and will come up with some sort of social event to go along with it. A taco day would see a more extravagant meal offering, but might also have theme specific mariachi music being played, along with the potential for alcoholic beverages, dancing, and so forth.
Themed dinners take on a greater importance on small and medium ships, as larger ships have the ability to carry more than one special meal day a week. These larger ships also have less of an ability to mount a ship wide special meal that the entire crew will agree on.
3. Card Night
A relatively simple thing, card night has the various members of the crew invited to play at cards. This simple game, gambling with a pack of cards, is cheap, and allows for socializing between different departments, different sections of the ship. The aspect of gambling can run from basic wagers of currency, to more esoteric offerings like rations, personal belongings, covering work shifts, and so forth.
4. Game Night
A more modern approach to the card night is the game night. Rather than a deck of cards, game night can revolve around any number of popular games. This can range from basic collectible card games, fantasy sports leagues, tabletop war gaming, RPGs, playing video games. Not everyone has interest or patience for five card stud or Texas hold'em.
Most ships that indulge in this sort of gaming are not going to require the crew to bring their own games, card sets, or painted armies. Instead, they will have what amounts to a ship set, that stays as the crews rotate in and out of the ship. Crews that serve more than one long haul on such a ship are likely to buy new pieces and packs for the games, creating ever evolving fields of play. More well equipped ships might have the option to print new pieces, or print new cards, just to keep things fresh.
5. Sex and Drugs
Strongly frowned upon and actively discriminated against on most ships, sex and drugs are not uncommon on ships. There are a number of reasons that this is frowned up, the two largest reasons being the potential for accidents and disasters due to crewmen being compromised by intoxication or emotional turmoil, and that on a long enough trip, the drugs will run out, and people engaged in large amounts of casual sex are invariably going to come to odds with each other.
Guppies, or Gay Until Port, are crewmen serving on predominantly single gender ships, who engage in homosexuality as a method to stave off boredom and a lack of human contact.
Conspicuous Promiscuity is a more common practice on ships with a relatively even balance of men and women serving on a ship. CP in and of itself is not much more than polyamory, but it runs into problems as it is easy for chances of STD outbreaks, unwanted or unexpected pregnancies (that many ships are not equipped for) or outright hostilities over the basic fact that humans who regularly engage in sexual intercourse are going to develop emotional connections and a desire for exclusivity.
Drugs come hand in hand with smuggling and other illegal activities. There will be drug dealers, and the dynamics of power of the dealers over the users. This can create a position of a well stocked drug dealer having the social power over the crew to foster loyalty among the crew, allowing for potential mutiny. Drug users also have withdrawal, violent tendencies, and worse.
6. Idle Sims
The vast majority of Cognet programming is streaming, and interconnected. Cut off from reliable stream sources, many ships have what are considered idle sims. An idle sim is a closed game world that doesn't have multi-user access. These games are generally harmless, and run the gamut of classic fantasy tropes and harem genres, the danger is that after a long period of time of isolation inside an immersive environment, some users will develop personal and behavioral disassociation, preferring the sim to real life. Most sims have safeguards on user interface, but old code and old source games can be hacked, modded, and otherwise changed to the point where instead of being distractions from the tedium of space travel, they become siren traps, encouraging destructive behavior or exploiting flaws in the user psyche.
7. Vigorous Self Improvement
Also known as vigging, VSI is when a crewman decides that with all of their free time and lack of distraction they are going to do some vigorous self improvement. The most common outlets of VSI include working out and spending time in the gym, enrolling in virtual higher education (or reading every book available on the ship) code and computer programming self-education, or following an intricate and demanding hobby such as perfecting a Japanese tea ceremony, calligraphy, and so forth.