Minecraft needs bathroom fixtures.  Sink, shower, bathtub, toilet.  Different materials would be nice, but white porcelain would be good enough.  Villagers need to use them.  Have them sing in the shower with their weird little voices.  Have them occasionally take a dump or wash their hands throughout the day.  Of course, there needs to be redstone interaction--comparators, hoppers, etc.  In honor of the guy who said, 

“You need to get out of here because I’m fixin’ to blow it up.”

Creepers should also be able to use the toilet.