les aléas de la vie : twists that life throws at you (usually positive)
une crevette : literal- shrimp, slang- 1) a wimpy/non-buff guy, 2) someone who has a nice body but a not so good looking face [comes from the fact that you rip off the heads of shrimp when you eat them, LOL]
un tombeur / une tombeuse : a lady-killer / a hot mamma
patati-et-patata : 'blah blah blah'; 'and so on, and so forth'
une peau de vache : literal- the skin of a cow, slang- a mean girl
*NB* it's equally mean to use it! :P
un loup dans le nez : literal- a wolf in the nose, slang- a booger
*NB* typically used by very young children