His roommates' plan for him was hydration!
Ross is an engineer. Ross's roommates, apparently, are not. They thought it would be a funny prank to fill over 200 paper cups with water to make it take forever for Ross to get to his room. Instead, Ross used science to make it less fun for everyone except himself. Science makes things less fun. Lesson learned. Here's what he did:
Aww, weight distribution <3's you too!
Because who doesn't have an old board lying around? Non-engineers is who!
Now Ross is the king of his castle, and only people who understand physics may enter. Woot.