Crapenstance 

An unwanted run-in with a stranger. It can be a brief or long encounter.

I just had the best Crapenstance. This homeless dude just tried to tell my fortune.

This nerd wouldn't stop singing on the subway, the whole time... Crapenstance.

Crapenstance by sqrell November 10, 2012

Crappenstance 

A chance circumstance that degenertates into crap

an event that might have been arranged although it was really accidental that turns into a balls up, nightmare.

Bob met Ted by crappenstance, Ted was going down on Bob's wife at the time.

Crappenstance by Nonsensical_Flounderings May 9, 2005

campenstance

Any number of random occurrences incidents, or mishaps that take place during a camping trip (usually as a result of massive alcohol consumption).

Ken burnt a hole in his pants while jumping over the campfire to get another beer out of the cooler. We just chalked it up to campenstance.

campenstance by G-love13 February 11, 2009