ChronoSlider Lite is a nice tiny tool to help you manage alarms and timers with a single mouse click on a unique user interface.
Set an alarm or timer by sliding your mouse across the screen and click once to confirm.
The full version, which is also available on the Mac AppStore provides many other featres:
• Global Hotkey – access ChronoSlider from anywhere
• Custom alarm and timer messages
• Repeating alarms