The Top 95 boot screen.
Top 95 is a fictional Linux distribution first mentioned in Stunt Vid 3 and first seen in Stunt Vid 4 running on Geoff's computer. In Stunt Vid 3, Joel notes Top 95 as his favorite Linux distro when asked by Keith.
Top 95 as it is seen in Stunt Vid 4 is actually Ubuntu MATE with a classic theme on it.