I was reading online about eye boogers and I guess the ones my bunny has are called sleepies. What are sleepies, what causes them, and can they effect my bunny in a bad way? Please help! 

like what IsabellaRobyn said - It's normal if it's just a little hard piece, (though you may find it before it hardens). It's like what humans get. Usually bunnies groom it off themselves eventually. When I had two bunnies, they would clean it off each other. It's the way eyes keep themselves moist during sleep I think and prevents tears from escaping out, (via this oil secretion) and then it catch dust, etc and begins to wash away as we wake up and "blink". They can turn hard, and if they don't come off easy from your bunny, you can get a damp warm cloth and gently wipe them away.