I used to know someone with a glass eye. It was one of those old style ones that look really artificial and scary though. He was a bit of a weirdo to be honest, everyone was scared of him when we were kids because he'd chase you with it while having a manic expression on his face. As he got older, he'd pop it in the drinks of random people in the pub, and still didn't bore of chasing people down the street.
He then progressed to working in a chicken factory and for amusement, he's pop it on the conveyor belt (covered in blood) to scare people, then suck it clean before putting it back in.