Okay just off the top of my head:
Blackmail - In any form, but I was thinking maybe an couple desperate for kids, female has an affair becomes pregnant to the man, pretends the child is her boyfriends and can lose it all if the man reveals the baby's true parentage.
Runaway - Typical teen angst-ridden impulsive action I guess, maybe she/he comes back toting a child? Or a serious addiction?
Money - Sudden influx causes instant fame and friends come crawling out of the woodwork; or sudden loss of job/work/income and become poverty stricken, could even go into the types of unscrupulous work they might be forced into.
Don't know if these are any use to you but I guess it's better than nothing *lol*

Good luck with your writing!