sys.warchall.net is a polish website with a lot of challenges. You can find here hackmes, crackmes, cryptography challenges, programming tasks, logics/riddles, theories and more other stuff.
A lot of tasks for begginers, more advances and experts - Show Your Skills
On the page with the challenge number ,author and points,
you will see boxes with + signs on them.
after the points number and before the + sign is some whitespace,
answer goes in there, then press the + sign.
h and the links don't work on the Niestety page,
just use the back button your browser.