Just a little exercice to discover notty. It does display the time. And can be used for countdowns.
Run to get time, press Enter to stop the clock. It does support resizing \o/. Press c to trigger the countdown, then enter digits and press c again to start it. A third c will reset the countdown. The background will blink during the last 5 seconds of the countdown.
Run make and then ./nottyme.native. You need notty and lwt.