I learned this game from a fellow teacher in the Intensive English Learning Program at LaGuardia Community College, CUNY, who played it as a child.
It's a pairs game (or chain game), where each player picks up from the previous player's contribution.
The joker starts the game, usually with the standard opening, "Unfortunately, I fell out of an airplane."
The next player continues the story, but switches the direction, "Fortunately, I had a parachute."
The joker (or a third player, if it is a chain), continues, "Unfortunately, the parachute had a hole in it."
The next player, "Fortunately, the hole was patched."
"Unfortunately, the patch came off."
"Fortunately, I had a back-up parachute."
"Unfortunately, I left it on the plane."
The goal is to create a fun, interesting, story. The only rule is that you must alternate between "fortunately" and "unfortunately."
Watch for: the best sentences are limited to one fact, if you make a sentence with too many steps or elements it makes it harder for the next person to switch direction. Bad: "Unfortunately, I fell out of an airplane and crashed to the ground where I broke my back and skull." Good: "Unfortunately, I fell out of an airplane."
Variations: try a different opening line, perhaps a thematic one.
"Unfortunately, I was fired from my job."
"Fortunately, I had lots of money in the bank."
"Unfortunately, the bank invested all my money in junk bonds..."