I want to do something like this with EE:
jsfiddle.net/vU9Hv/1
But I want to be able to select multiple categories. Like Category 1, 2 and 3.
I also asked this question here:
http://stackoverflow.com/questions/11038987/how-to-select-multiple-buttons-and-display-these-filtered-results-dynamically
That above link has the example in a JPG.