The greatest amount of time you will spend using this polling tool is coming up with cool questions related to what you want to know. There is not signing up required, nor accounts to take care of. Once you make your poll questions, copy the code into a wiki page or a blog and send the link to your students. Their participation will remain fully anonymous, but you will gain a lot of information and take the 'temperature' of your classes. Remember you should do your polls in your language, right?
The link to the tool is: www.flisti.com .
Sample poll questions (simple and silly?)