During their sophomore year, roommates Arun Rodrigues and Kevin "Perk" Hennessey covered the entire ceiling of their dorm room with plastic 20-ounce Sprite bottles hanging from their caps. It was a start. Junior year they added a waterfall. This year: American flags, a giant poster for the punk band Dead Kennedys mounted on a motorized roller with remote control, 1,200 Christmas lights, and their crowning achievement -- a Chuck E. Cheese-style play pit of colored plastic balls. It's no wonder that their home, 329 Keenan Hall, has become perhaps the most famous dorm room on campus, after President Malloy's in Sorin Hall. In November it won first place in a decorating contest sponsored by _Steamtunnels Magazine_, a national publication inserted into college newspapers, including _The Observer_. They received a $100 gift certificate to Amazon.com that they plan to use to buy more unique items for the room. The room attracts so many visitors that Rodrigues and Hennessey have had to post a list of answers to frequently asked questions outside their door. Two of the most common are "How?" and "Why?" And their answer to both is, "Because we're engineers." Rodrigues, a computer science major from Michigan, and Hennessey, an electrical engineering major from Missouri, say they wanted a unique room. The concept just mushroomed. The waterfall, in one corner of the room, runs on a pump that circulates water through plastic ivy and flowers hanging down the sides. They constructed the ball pit, about the size of four playpens put together, from plastic pipes. Thick plastic sheeting forms the walls. The pit contains 9,000 colored plastic balls that they ordered over the Internet at a cost of about $1,000 ("and worth every penny," insists Rodrigues). Access is via a wooden ladder on one side. The structure is actually quite sturdy, having survived a party with only a few rips, they say. For those who can't make it to Keenan Hall, the roommates' website - see links - features pictures of the room and a list of "rules of ball pit," which parodies the "rules of fight club" from the movie _Fight Club_. The eighth and final rule of ball pit is, "If this is your first night at Ball Pit, you have to jump into Ball Pit." In fact, visitors are welcome to try it out, provided they respect the others rules, like "no shoes." Another frequently asked question about 329 Keenan is, where do its residents sleep? The room no longer has any beds, only a makeshift loft Hennessey sleeps in when he's not sleeping at the computer lab, which isn't often. Rodrigues says he either curls up on the floor or hops into the pit. "It's extremely comfortable. You are sort of suspended in the air when you sleep in the ball pit. You can't really tell if you are on the ground or not. It's a neat feeling of floating."