it took me a while to read this article b/c of all the videos, but it was pretty interesting. my little brother has a couple of these games, so i may have to have him go through & find some of these. link
Not going to lie, those are all creepy. But the most creepy video game part for me was 'Bleeding Walls'. I forget what game it was, and I don't think it was an Easter Egg, but I'm still terrified of it.