The clock that came with my Mac is just a clock. Keeps good time, but it doesn’t have an alarm or timer feature.
I might be surfing and say, “15 minutes and then bed-time”, but then I wander into the SDMB, and start reading and posting, and at about 2 a.m. Mrs Piper comes down and says, “Aren’t you coming to bed??”
So, a timer feature would be nice. One that I could set for a certain time or time period, and when it goes off, there’s a chime or something.
The ProdMe Dashboard widget can do chimes every five, ten, fifteen, twenty or thirty minutes or on the hours, as well as serving as a regular alarm clock. It has a variety of sounds, some more startling/annoying/alarming than others.
Meditation Timer is a very straightforward countdown timer, with a pleasing starting and ending chime, as it’s meant to facilitate meditation and yoga. But it holds the time you set, so if you want to give yourself, say, 15 minutes of recreational websurfing before bed every night, or do regular 6 minute intervals away from the computer to avoid RSI, you can just click the start button and there you go.
MP3 Alarm Clock is a very full-featured OSX app. The pluses here are multiple alarms for various days of the week, and you set it to use your own music, rather than alarm noises or the various system pings and booples. You can configure snooze times, messages to play, randomize the playlist of music that plays with the alarms, gradually increase the volume of playback for a more gentle awakening or nagging experience, and also gradually increase the speed of music playback, so that if you ignore it for too long, you’re eventually listening to the Chipmunks.
All three are free, and run on Jaguar -> Snow Leopard.
Ironically, the PiperCub has been waking me up in the middle of the night so often recently that I’ve not had the energy to try any of them out! Perhaps this weekend, if the Cub will take a proper nap.