Hey,
I recently downloaded something from Demonoid which usually has about 5 GB. (Battlefront 2)
The good thing was, some guy compressed the whole thing into 329 MB!
The description:
Star Wars Battlefront 2
Ultra Compression
It will unpack into a full-fledged game (4.88GB)
Be aware, it can take a while to unpack
So here we go:
Go to this page and download Uharc WinUHA - UHARC GUI - Download .
After you're done install it and click on the top on "Help" and then "Uharc Guide" or something like this.
There's written how you use it correctly.
Have fun compressing!