This mod adds drugs into minecraft. You can farm them, buy them, and consume them. It uses shaders, so you can guess the effects are actually worth something. Beware, though: It may make you feel dizzy
It also adds one or two new overlays. You can disable them in the properties file, if you want to.
How to install:
Download and install Minecraft Forge.
Download the mod and IvToolkit.
Go to %appdata%.
Go to .minecraft/mods folder.
Drag and drop the downloaded jar (zip) files into it.