Rifts is a post-apocalyptic fantasy role-playing game from Palladium games. It's an incredible game; I recently got a copy of the 1990 core rulebook (first edition, not unlimited edition), and I'm planning to write an in-depth review. This page is my placeholder.
For now, I direct you to visit http://www.fractal-cortex.net/rpg/, it's a repository of (hopefully legal?) files pertaining to RIFTS, D&D, and Exalted.
I also implore anyone interested in RIFTS, Palladium games, or Role-playing games in general to visit and watch the "From the Rifts" series on youtube. A simple youtube search should suffice.