3. Skyrim - Minecraft Tribute
The highest point in all of Tamriel, the Throat of the World mountain home to the Grey Beards and Paarthurnax, this mountain also has buried in it a nice little Easter Egg that pays homage to the hugely popular Minecraft phenomenon. The "Notched Pickaxe" is clearly both fan service (considering the amount of players who would have clocked up a lot of hours in both games) as well as a tip of the hat to the game itself. It's high worth and extra features makes it a significant artifact rather then a simple throwaway set prop, which makes its discovery all the more essential. And obviously, the difficulty comes in the fact that it isn't just lying around on the floor like some discarded Goldeneye golden gun. It's always good to see development companies supporting one another, and although there were legal battles occurring between the companies of Minecraft and Skyrim the development teams still maintained a degree of professional respect through these references.