I once had a small website. I remodeled it several times. Each time I would download the current database, run it on my local PC and make sure everything worked on my PC and THEN I would upload it to replace the old site. It meant there were literally only seconds the site was offline for an upgrade. Whoever is doing the work on clemsontigers.com is not doing it right. Only thing I can think of that may cause such a delay as this is if they are migrating to a different host. In that case they would have to allow a few days for DNS propagation.
Not this long. That usually takes a max of 72 hours. All I can guess is something more political in nature happened to have caused the shut down/ redesign. If this update was planned and scheduled it should have happened smoothly and with little to no interruption.