Why do quarterbacks raise/lift their right leg before they hike the ball? I'm guessing some sort of timing thing to the wide receivers?

There are 2 main reasons for this:
1) Signal a receiver to go in motion
2) In a shotgun formation where the line can't hear the snap count well, the QB will raise his leg as a signal to the Center that he is ready to accept the snap.

It's a signal for the widereceivers to go in motion before the hike.

Passing gas. It really hurts to get smashed with a colon full of methane.

Usually a signal to start a man in motion.

If they're in the shotgun, it's a signal to the center to snap the ball.

To put the receiver or running back in motion

This is for different number of things. It tries to throw the defense off guard , by thinking the quarterback is going to drive off his foot . It also sends a man in motion, or they just do it because everyone else does it.

that means they have just ripped a s s !

they got gas....that and to signal motion, usually by a flanker.

its a signal to the blimp above the stadium to zoom the camera in on his green dot...

They are marking their territory.

yeah it's out of instinct, any time a guy is gonna throw something out like that, he's gotta feel comfortable about it.

they do it for the say reason that guys playin baseball do, cuz there so hood. lol.. they just do..