About the licensing;
The content posted on here should be just Public Domain (also called CC0); although when you use stuff from this thread, please give the original creator some credit.
Of course you can mention any other license, but if there isn't; then it's CC0.
Since the average knowledge of licensing, copyright and co. is very limited within the community, please don't confuse people with inaccurate information. Public Domain is NOT CC0. Public Domain is a very difficult topic because there is no common "Public Domain", every single country have another definition of Public Domain, including other requirements when a work is Public Domain.
In fact Public Domain has a lot of issues, that's why there is such a thing like
CC0 1.0. CC0 is basically a license which declares that the creator gave up his copyright and all other similar rights to the extent allowed by law + a Public Domain fallback for the case that the first thing isn't possible in some jurisdictions for whatever reasons.
Also while today there is only CC0 1.0, I'm pretty sure there will be more versions in the future. Please always note the license version. Quadropolis don't even give people the chance to select the license version for the license tag, so it's not very useful and just chaos. We shouldn't let this happen again.
To this topic in general, I like the idea that this could become a collection for all stuff which is inspiring, crazy or just funny, but not enough to deserve a standalone presentation.