Take control of gravity by simply pointing the arrow in the direction of your choice! Originally made as a private test, I put in on ToyBox with a great response.

Now you can play with it with your friends! Simply install the 'directionalGravity' folder (the one containing the info.txt and other folders) to your garrysmod/garrysmod/addons folder! It's that simple!
Type arrow_affectplayers in console to enable players to be pushed, and press E on it to turn it on or off.

Thanks to MacDGuy for his amazing arrow model.
A video of it in action: http://www.youtube.com/watch?v=9dp_cd43XBE