It wouldn't come out, no. The eyeball is actually connected to the brain itself via the optic cord, which houses the optic nerve and muscles required for eye movement. So in order to remove an eyeball, either the optic cord would need be severed, or the eyeball would need be severed from the optic cord itself.
As for what it would happen to an eyeball if it were stabbed with a pencil...
Go to your fridge.
Take out a grape.
Squish it between your fingers.
That's basically what it would look like. There are veins which supply blood to the eyeball but for the most part, the eyeball consists of a clear, jelly-like substance called vitreous humor. So while an eyeball will bleed, it won't bleed a whole lot.
One thing to consider -- it's very difficult to stab someone in their open, naked eye. A person can close their eye in a tenth of a second; normal human reaction time -- that is, the time it takes to perceive an immediate threat once it presents itself -- is roughly a quarter of a second. Which means chances are, a person will slam their eyes shut the instant they see that pencil coming at them. And while the eyeball itself might be impaled, you won't see it behind the closed eyelid.
As such, the closed eyelid will prevent any drastic leaking of blood or vitreous humor. Far more likely, the only blood you'd see would be from the punctured eyelid, and not the eyball itself.
