Corridor Blocks. Born in Year 10 from the need to rival the bundle. Bundles (frequently performed by idiots) were a real problem in and around Lab6 because of the arterial corridors being perpetually packed.
They didn't know what packed meant until then, though. Most of them were, come to think of it, performed outside Lab6 after a particularly rowdy chemistry lesson. Sometimes, people would be so desperate to leave the Lab (probably running from an advanced form of sink fill) that they would carry chairs out with them, which helped with the whole blocking process. One particular person was instrumental (and Vinné was just mental, but that is a very poor joke, worthy barely of the real yearbook) in the stopping progress by basically holding arms from one side of the corridor to the other. I imagine the were some injuries, which is why they are less common nowadays. The real fun was seeing how much Lab equipment would end up outside the Lab after the block.
Needless to say, it inspired the song Corridor Blocking Time.
A special kind of Block was performed rather admirably by the teachers themselves during an assembly, when everybody was trying to leave. More damage and injury was done in those five minutes than if they had just let us bundle out. For the record, people were riding out on chairs, on the wave of people.