I don't get it why someone would hack project euler.
...Hack This Site is a free, safe and legal training ground...
It's rather amusing how they claim they're 'legal', then.It took me a couple of minutes to get everything fixed, but I can only imagine what would have happened if they were more malicious and used it to serve malware or as part of a botnet attacking other sites.
It was still annoying, disruptive and unwanted, but it was so much easier to deal with than some more malicious hacks out there.