Here's how it works:
When you notice a vandal at work, take note of that person's IP number or handle.
Edit this page, adding the person's IP number, the date and the approximate time (server) of the vandalism.
Then put the person's IP or handle in the Summary box and hit save.
VANDALISM IN PROGRESS appears in caps on Recent Changes, along with the id of the vandal, and the rest of Wikipedia can jump in to help repair the damage (see guidelines below for how to combat vandalism). When the attack is finished, come back and remove the information you added.
Please only use this page for geniune malicious vandalism, and only for a sustained attack. If you make any changes to this page for other reasons, check the minor edit box, or put something like "Not calling a vandalism alert" in the Summary box.
Notes and further guidelines:
When you list times, please modify to "server" time for the international community. You can obtain the current server time from the preferences tab.
How to remove vandalism:
Some vandals enjoy the satisfaction of seeing lots of comments about their work in Recent changes. Hence to minimise the fuss, just enter the letters "VR" as a comment, and choose "minor edit". This informs the other editors that a page has been repaired, but keeps the fanfare to a minimum.