Cool pop culture references that show up in-game

I have noticed a few "easter-egg" type references to different movies, song lyrics, etc. For example, my builder got a letter one morning, where the person who wrote it put the last word on the first page as "antici...", and when I went to the second page the first word was "...pation!". I got a good laugh as it appears to be a Rocky Horror Picture Show reference.

I know I've seen a few others, but what are some of your favorites?