You can set it up yourself with relative ease. Clone this repo, then edit CSS, add challenges, and modify content as you wish (or none at all). Point a webserver at it, and you should be good to go!
If you have any challenges you would like to add, feel free! I'm always making more, so a helping hand would be awesome.
- Doesn't handle text-based challenges well
- No time limit for programs. Will crash the user's page if it runs for too long.
- Can't do multiple tries in one session.
- Quite a lot really.
Special thanks to Craig Buckler for the basis of the upload code.