This is an absolutely great episode that tells us how Leonard and Sheldon started living together. I loved it how Leonard was coming to meet Sheldon. And the cross dressing guy told him to go to the crazy guy across the hall. This joke would not be allowed today but it was pretty funny. We also get to see him meet Howard and Raj (Raj was somehow dressed as if it was 1980). We see where the couch came from and most importantly we learn about what happened to the elevator. Definitely a great episode.
Review of The Staircase Implementation
