Project M is a Super Smash Bros for Wii mod. It was discontinued early December 2015.
However, you can still find all versions here, without any pesky slow servers or ad-infested file sites!
The following was taken from the original Project M site:
REQUIREMENTS TO PLAY
The downloads below are for NTSC Brawl Discs and Wii's only. Japanese users, click here . PAL users: There is currently no release for PAL. Your SD card must be less than or equal to 2 GigaBytes in capacity to use Project M. Note: The Project M installation includes both music and textures as part of the standard package. If you have custom content on your card, it will be overwritten.
Please follow the instructions below. Note: The instructions are for the Hackless method. If you're using a Homebrew method, simply delete any previous version of Project M, extract the files to your SD card then boot Homebrew and select the Project M Launcher. If you are using the Installer, you will prompted to select a package to download.
- Delete any custom Brawl stage files on your Wii and SD Card! Don't assume that because you haven't made any there aren't any; 3 custom stages are included with a new savefile of Brawl.
- Delete any previous version of Project M from your SD Card and make sure the card itself is not named "Project M" or any derivative thereof.
- Unzip the file and open the folder that comes out, or use the Installer to download and generate the folder instead.
- Move the contents of that folder to your SD Card.
- Remove any Gamecube Memory Cards.
- Boot up Brawl and go to the Stage Builder.
- The Project M Launcher will boot; select Launch Game.
- You will see a straploader saying Project M 3.6. Additionally, if your menu image looks like the image below, then go ahead and play and enjoy Project M!