Jinx is a nickname given to that tall, easy-going person, who seems to always get the girls. They are incredibly intelligent, and musically talented.
Person A - they've got a date this weekend.
Person B- that's Jinx for ya.
An exclamation used after something anticlimactic happens.
Person A- * drops mentos in coke *
*nothing happens*
Persons A and B- Pancake!