When I was in my 20's my husband and aI were asleep and I woke up abruptly at 4 am. I felt someone "bump" into the end of our bed, then felt the mattress press down near me as if someone were sitting there. I woke my husband and told him what I had felt, he brushed it off and told me to go back to sleep. I finally went back to sleep and then was woken by the phone at 8 am. My grandma was calling to tell me that my great grandpa had passed away just before 4 that morning. Then I realized, it had been him sitting on my bed, I would guess to say good-bye.