One such place is http://www.reddit.com/r/samplesize
You don’t need a Reddit account to do the polls; just click on the title and you will be well on your way to scratching that sample itch.
I will note that not all samples are created equally, these are most/all created and maintained by individuals. Some people do post the results after a few days, but that’s not always the case. They also don’t necessarily have sensible answer options, but most of the polls are well-formed.. I will also note that, while there is lots of interesting and thought-provoking content on Reddit, there can be mature content (even in polls). Viewer discretion is advised.
I plan to link to the occasional survey from Reddit, and will consider putting my future ones on there also. But don’t worry, I’ll still provide a link to it here also!