Are you tired of gravity being very limited in Minecraft?  Do you want to be able to send chests down and up long distances?  Have you ever wanted to send a redstone block down at your enemies, then send down tnt?  The Falling Blocks Custom Command might be what you're looking for!

Hello PlanetMinecraft, this is Sharpman76 with yet another command.  Sorry I haven't put any out recently, I was having artist's block.  I came up with this idea, and I hope you find it entertaining if not practical.  This invention gives you the ability to give gravity to any block imaginable, and if the block is holding anything (like a chest) the contents will not be lost!  You can also reverse the gravity of these Falling Blocks and have them soar into the sky (until they hit the height limit).

Disclaimer: The Falling Blocks don't actually turn into entities, the blocks are just being /cloned down/up a space, so there are some pros/cons.  You can't fall through them, they won't break on torches/pressure plates, and they fall so fast that if you stand on one for a period of time while it's falling, you will likely lose a lot of health.  Just thought I'd let you know.

In this contraption, there aren't really any recipes, so I'll just say everything here. To make a Falling Block, place a gravel, red sand, and sand in a stack on top of said block, as seen in the picture.  Stand on top of this stack to convert it.  If all goes well, the sand and gravel should disappear and white smoke should start to come out of your Block.  If this happens, you have succeeded.  The Block will fall down if an air block is beneath it.
Breaking the Falling Block will just transfer the gravity to the block below/above it, so in order to de-gravitize your Block, hold a wooden shovel near it.  You should get you sand/gravel back, and the block should stop smoking/falling.
To reverse gravity and make your Falling Block a Floating Block, throw an ender pearl near it.  The smoke should turn purple and your Block should go up.  Throw a snowball at it to turn it back to normal.
Blocks will stop rising/falling when they reach the bottom/top of the world.  Sorry, no holes to the void for you.

I've used tryashtar's 1.9 Command Compactor for all my commands so far.  Go check it out!

To set up the custom command, type the command  "/give @p command_block" in your chat window and press enter/return.  Place the block down, paste the command into it, then click the button in the interface that says "Needs Redstone" to make it say "Always Active".  Press "Done", and it should set up.  To get rid of the machine, make the outlier block that has a fill command in it "Always Active" . 

If you have a bug, question or suggestion, don't be afraid to leave a comment.  Telling me bugs helps me improve the command, and asking questions helps me improve your experience working with my commands.  Please give me suggestions, as I'm running out of ideas and I like a good challlenge.  If you like the command, feel free to leave a diamond.  Tell your friends about my profile so I can grow my following.  ¡Adios!