This is a port of my Doors CS 7 Clock to the TI-84 Plus CE using Celtic CE. It will work with any shell that supports monochrome icons, as long as Celtic is installed. This is sort of a proof of concept as every shell basically has a clock anyway.
Install the latest release of the Celtic CE libraries from the GitHub according to the instructions here.
Send CLOCK.8xp to the calculator, and run it whenever you want to update the time. (The program must be in RAM and Celtic must be installed for it to work properly)
TIny_Hacker, who wrote the program
RoccoLox Programs, for Celtic CE
BioHazard, who fixed my stupid bug and suggested ideas
Kerm Martian, for SourceCoder3 which I used to make the icons needed for the program
LogicalJoe, for optimization to reduce the program to < 500 bytes