I think the The Thread of AWESOME! at Adventure Rider has some cool, funny, weird stuff - like this awesome video about how an octopus can camouflage itself by changing it's skin color, pattern and texture.
There's a lot of different stuff people have posted on that thread; here are a few other videos that I thought were cool -
Brickies Labourering in Bangladesh
MikroKopter - HexaKopter.