For the last couple of days I've only been listening to Them Crooked Vultures bootlegs. They might honestly just be the greatest thing ever to happen to music. It's Josh Homme from Queens of the Stone Age on guitar/vocals, Dave Grohl on drums, and John Paul Jones from fucking Zeppelin on bass/keyboards. I got to see them Thursday and nothing has ever been this awesome.
Your is possessive. In other words, you own something.
Ex: Your new baby alien loves to cuddle, but he keeps crapping in your refrigerator at night.
This is referring to your alien and your refrigerator.
You're is a contraction of "you are."
Ex: You're definitely cleaning out the fridge in the morning, assuming that little bastard can't keep his bowels in check.
This translates to "You are definitely cleaning..."