Muck-up Day is traditionally Australian, but the UK has adopted the term from television shows like Home and Away and Neighbours. Muck-up day was a common practice in all schools in Australia until the 1980s, which was when principals started banning the practice. Most Australian schools still continue the tradition, but on a smaller scale. In the UK it is still common amongst private schools, and often members of staff (particularly grounds staff and porters) at the school will unofficially assist the perpetrators.
Many rival schools prank other schools that are considered rivals rather than their own. This causes the rivalry to grow.
Common pranks pulled either within the pranksters own schools or rival schools are; egging of buildings, graffiti, vandalism, trespassing, releasing of animals within buildings, moving of statues or monuments, starting barbecues in unusual places in unusual attire and using water pistols with anything but water in them.
Usually the school will announce a student free day (day off), on muck up day for the rest of the year levels to ensure the safety of other younger students.
In Victoria, the 2006 muck-up day took place from the end of October till mid November, with the exact date depending on the school.
In South Australia, pranksters use their cars to drive around school areas and graffiti schools property and the cars of students who attend that school. It is labeled by the delinquents as the spray'n'flex. On the night before muck up day, schools place tight security around the grounds preventing any damage caused by students.
In Western Australia the term "Muck-up day" has been changed due to people thinking that the term misleads students into doing the wrong thing. A 'better' term "Activity day" has been used at some schools to take away the bad connotation. Some schools still hold a traditional activity that involves students and some teachers throwing muck at each other. Students usually have more than a week to prepare a bucket load of muck which may contain off dairy products, eggs, jelly, seafood, pasta, rice and colouring. Although some students have used bioligical components such as animal blood and meat, schools check to make sure such things are not used. The activity is situated at a place decided by the school. Students wear clothes to cover up as much of their body as possible, painting suits and shower caps have been most favoured. At the end of the activity those who participated are almost entirely covered in muck of all sorts of colours and pungent smells.