A website consisting of “hacking” challenges of varying difficulties. It’s been around for a long time now and I remember having some fun with it back in the day when I was younger.
The site still works and you’ll need an account to tackle the challenges.
Does anyone remember notpron? Very similar concept and much fun! Legend says one could even earn a certificate upon completion.
Of course I remember notpron! I even thought about it when making the post, but I couldn’t remember the name! Apparently notpron is still online and can be played, so I know what I’ll be doing now :D