Minecraft's 1.5 Redstone Update has been published, and a recent video shared by developer Mojang on its official blog walks viewers through its many changes with a song.
Check out YouTube user YourMCAdmin's video above to learn about hoppers (which collect items and move then to containers), droppers (which are like dispensers, but always drop items), daylight detectors and more, all of which can be downloaded in the 1.5 update through Minecraft's multiplatform launchers.