Caffeine for Mac - Caffeine is a tiny program that puts an icon in the right side of your menu bar.
Caffeine for Linux - Inspired by the Mac OS X version, Caffeine for Linux is a status bar application able to...
Caffeine for Windows - Prevent your computer from going to sleep
SmartSleep - SmartSleep lets you select each sleep state.
NoDoze - NoDoze simulates keyboard/mouse activity to keep the screensaver from activating.
AntiSleep - AntiSleep is a powerful software that prevents the system from going into hibernate mode.