Just for fun - how far ahead do you plan your travel for SC? [http://sc13.supercomputing.org]
Are you the kind of HPC person who books SC13 as soon as SC12 has ended? Or do you leave SC13 travel booking until a week or two before SC13? Of course, it may not be up to you - many attendees need to get travel authority etc. and this is often hard to confirm a long time in advance.