Ooh, what about one of the supernovas:

SN 1006 (The Brightest)

• Date: April 1006
• Brightness: Reached a magnitude two or three times brighter than Venus, casting shadows on Earth.

SN 1054 (The Crab Nebula Creator)

• Date: July 1054
• Brightness: Visible in broad daylight for 23 days and stayed glowing in the night sky for nearly two years.