Algorithm: How to use x and y mouse movement co-ordinates to generate random data?
The PuTTYgen program, which is open source, contains the following comment in WINPGEN.C where it collects mouse movement for key generation:

/*
* My brief statistical tests on mouse movements
* suggest that there are about 2.5 bits of
* randomness in the x position, 2.5 in the y
* position, and 1.7 in the message time, making
* 5.7 bits of unpredictability per mouse movement.
* However, other people have told me it's far less
* than that, so I'm going to be stupidly cautious
* and knock that down to a nice round 2. With this
* method, we require two words per mouse movement,
* so with 2 bits per mouse movement we expect 2
* bits every 2 words.
*/


I don't know how accurate this information is. I just remembered seeing it and though it was worth sharing.