<p>Sleeping Bag Weekend/Sunday is only for admitted students during April; other times during the year I believe it is on for Seniors (or people applying to colleges that year). I highly recommend going, if you can find the time/money to get to CMU. It really helped me solidify my decision to come here (after going to similar programs at USC, Rice, and Northwestern).</p>
<p>Keep in mind that CMU does charge a fee that covers food for Sleeping Bag Weekend, so if your friend is not officially registered, he won't have meal tickets. Also, I've been a host before, and will be again... I need to sign up... and I wouldn't exactly be happy if two people showed up instead of one. Some rooms on campus are small (particularly New House and Hamerschlag) and may not be able to accomodate you and your friend sleeping on the floor.</p>
<p>On the 28X (bus from airport to CMU)- all you do is exit the airport on the side for buses to hotels and whatnot, and walk outside until you see the sign for the 28X. The bus comes about every half an hour. You get on, pay $2.25 (must have exactly change) and sit on the bus for roughly an hour. CMU is the last stop. Shouldn't be hard to miss- quite likely there will be a large pole marking campus by the time you come.</p>