Looking for a simple way to remind yourself when to leave work in time to catch your train? Or to let you know when it’s time to meet friends for lunch?

On a Mac, you can do this sort of thing with iCal, but for simple little reminders like this I prefer Pester, a simple alarm-clock freeware program by Nicholas Riley. The interface couldn’t be simpler: to create a new alarm, just type the alarm message you want displayed, the time (hours:minutes from now, or absolute time/date) into the window. The Dock icon displays time until the alarm, and at the alarm time Pester foregrounds itself, displays your message, and gives a system sound. Just click enter to dismiss the alarm. Setting an alarm takes only 15-30 seconds, and Pester just runs quietly in the background without consuming any system resources. You can set multiple alarms, but you can’t set recurring ones. But then, that’s what iCal is for. Pester is just for the little things, but it’s great for them. Works on any Mac hardware running OS X.