As you mention, your school is blocking objectional videos - they are probably blocking *all* videos, hence none of these will run. I venture that you're out of luck. Before/previous years, the workaround was to download the files of the videos (*.avi/whatever) and watch offline. Maybe someone else knows how to do that this year when the videos come from that video provider site (blip.tv?)
By the way, our school blocks *.zip files - which is a pain - but the workaround is to download at home and bring in on a USB drive.