I want to use a TV as a sweet "diagnostic monitor" but I don't know where to start.

I have a samsung TV plugged into my system as a second screen that I want to use as a "diagnostics and pretty-terminal-stuff monitor".

I'm green with, but getting to know tmux. The thing is, aside from the top family of programs and maybe wireshark, I don't know what else I can use to monitor my system at a glance, or just be some cool visual noise-generator.

What are some other terminal-based system-monitoring tools or cool stuff I can use to turn my TV into a one-stop-diagnostic screen?