It happens sometimes. Reasons we can't control come out to grip some, or all, members of a play group and before you know it the session is cancelled. The question then becomes: what do you do now?
Now, obviously if you're one of the people that reality got a choke hold on, the answer is obvious. But what if you're just one of the innocent bystanders? What if you were ready to go and now the game is gone? Whether you think about it or not, a game session being cancelled means you suddenly have 4-6 hours back in your day/week/month that you weren't planning on having. It also means that one of your social events to see friends, relax, and unwind a little is also gone. So, what do you do?
The responsible answer is to do something productive. Get some homework done if you're a student. Catch up on work around the house. Catch up on work for work. Get ahead on work for work if you can. But the problem here is these answers aren't all that fun, and more seriously it is taking your destress time and making it into stress time, which may not be a good thing.
Personally I find it depends on the day, but I like to do a lot of things. Sometimes the opening is perfect to go and see a movie. Instead of 4-6 hours of gaming you just head to the mall, buy some fake chinese food from the food court, and see a 2 hour movie. Takes a similar amount of time, still relaxing, and you get to see a potentially good movie.
Other times I'll play video games, read a book, or otherwise just find something to help me relax. Videogames often work best for the combination of involvement and vegging out, especially if I have a story based game - like most RPGs - to go through still.
How about you?