About 3500 fans showed up at the Washinomiya Shrine in Saitama in conjunction with the Lucky Star event with guest appearances from the seiyuus from the show. - Source
Sigh, unfortunately for me, I was there a week earlier, and didn't know about this event till like a week prior to my departure to Japan. Apart from the opportunity of meeting the voice actors, the event also boasted Lucky Star merchandise solely available there. Damn it!