show text on logo hover in over
I think that the best way to go is jQuery.


Create new block with text that you want to show
Using CSS, set block position that you want
Set display:none; for that block
Add jQuery script in your block (or implement on some other way).


Script should looks something like:

jQuery("#logo").hover(
        function () {
            jQuery("#blockId").fadeIn(); //change the blockId with Id of your block
            jQuery("#block-views-projects-block").fadeTo(1000,0.5);
        },
        function () {
            jQuery("#blockId").fadeOut(); //change the blockId with Id of your block
            jQuery("#block-views-projects-block").fadeTo(1000,1);
        }
    );


Of course, if you add this code in your block, it must to be added into &lt;script&gt;...&lt;/script&gt; tag.