System47 is a screensaver that simulates the famous LCARS computer interface from Star Trek: The Next Generation and its successors. Diagnostic screens run showing the layout inside the Enterprise-E while scans display information about astronomical phenomenon. It's extremely well done, and perfect for anyone waxing nostalgic about the good ol'days of Star Trek. Window XP and Mac versions (up to Tiger) are available, but unfortunately it doesn't run on Mac OS X Leopard.