I recently discovered a very cool package called cool-retro-term. It’s a graphical terminal emulator, like xterm or Terminal.app, which is designed to look like various kinds of old monitors. For example, this is a system monitor running under my personal preset (click to see an animation):
Obviously, it’s not the most practical tool, but it’s certainly interesting and can lend an air of the 80s or 90s to any command line program given the right presets. The default presets include Apple ][, IBM DOS, and many other classic computers.