NFS SkyscraperClock 1.1
Here there are screensavers of nature, natural phenomena, screensavers showing time, and others. The screensavers from http://www.newfreescreensavers.com are initially designed to prevent damage to CRT and plasma computer monitors by blanking the screen or filling it with moving images or patterns when the computer is not in use. The screen saver starts automatically if your computer is idle for a specified amount of time.
Clearly free screensavers. No spyware, no adware, viruses free. It's safe to install and run.