Don't trust your system random number generator or websites claiming to provide you with random numbers or random passwords? You are right, these can probably not be trusted. So what now? Here, you can generate your own entropy that is then used to create a password (in several formats) of a selected strength. This website does not submit the generated passwords or your entropy image anywhere (look at the code!) and if you do not trust me, download the website, unplug your computer, generate your passwords offline (!) and then, if you are still paranoid, format your hard drive, get a truck to run over your bios flash and whatnot. More info about jspwgen here and here.
This site is provided without guarantee that it will work - maybe I made some mistakes and the generated passwords are not actually that strong... But I use this page myself, so for me it is good enough.
Move mouse randomly in rectangle below. You should see some dots being generated at your mouse position. If no dots are generated, do not use this website to generate passwords!
Fill the "weak entropy" bar to get a secure password for anything below 80 bits. For stronger passwords, fill the "stronk entropy" bar.
Acknowlegdments to http://silentmatt.com/biginteger/ and http://crypto.stanford.edu/sjcl/