Don't know whether you've already covered these. These are fun
- telnet towel.blinkenlights.nl
That last one (telnet towel.blinkenlights.nl) is not always accessible over IPv4 from many locations in the world, including the USA. The changes happened several years ago without explanation. I confirmed the problems a few weeks ago, but they are gone now. If you have issues with IPv4 and access to IPv6, try this equivalent command, which works from anywhere:
It is creative and clever and definitely worth your time to see what it does. It is harmless family-grade fun. It safe to run anywhere and does not change anything on your system.
Note: I tested it this morning before posting, and it is working from three separate locations around the US. It did not work from those same three locations a few weeks ago.