Eights Week is an Oxford University rowing and social tradition dating back to the early 19th century. It takes place in the 5th week of the Trinity (summer) Term, in late May or early June, and lasts for four days.
Eights Week features what are known as "bumps" races between 8-person rowing crews ("eights") from different colleges. The eights have staggered starts, as the Isis (that part of the River Thames on which the races take place) is not wide enough for boats to row side by side. The goal is to "bump" the boat ahead, either literally (sometimes involving significant damage) or by persuading the cox ahead to concede. The following day, the starting order for the two crews involved in a bump is reversed. A crew that bumps on all four days of Eights Week wins "blades", meaning that each crew member is awarded an inscribed oar and their names are chalked up in their college quads.