From Roger's Freeware:
Egg Timer is a simple count-down timer application.
Use the up-down arrows to adjust the start time, or enter the start time using the keyboard. Press the 'Set' button to set the timer to the selected start time. Then use the 'Start' and 'Stop' buttons to start and stop the timer. Once the count-down has ended, an alert window will open and system beeps will be played in 1 second intervals until the alert window is dismissed by pressing the 'OK' button.