You can take your pick of clock programs for the console; I’ve mentioned a few in past weeks that weren’t bad.
Narrow the field a little and focus on binary clocks, and tbclock is probably your best one.
Lots of options for display, colors, arrangement, hints, a stopwatch and even a simple guessing game for fun.
I like tbclock because it does everything you expect, adds a few frills to entice, and stops before it becomes something different.
A gold smilie for tbclock: 😀