I remember when Custom Corners was released by Urs Hunkler (technically quite a challenging this to achieve with Moodle) - and it was sooooo cool to have a Theme that had rounded corners on Blocks! Mary (a total 'Theme Queen') has done a great job in updating this, and as more Moodle sites update to Moodle 2.3, 2.3 etc. I think it will be one of the most downloaded Themes :-)