an adventure
Examples
War is not an adventure. It is a disease. It is like typhus.
Life is an adventure in forgiveness.
Every production of an artist should be the expression of an adventure of his soul.
The danger of an adventure is worth a thousand days of ease and comfort.
Liberalism, on the other hand, regards life as an adventure in which we must take risks in new situations, in which there is no guarantee that the new will always be the good or the true, in which progress is a precarious achievement rather than inevitability.
I get mad when people call me an action movie star. Indiana Jones is an adventure film, a comic book, a fantasy.