Some serious meditators treat conferences like Vesak as something unserious and far from being conducive to meditative practice and therefore achieving Nibbana.
Nevertheless, events like the Vesak Conference is a wonderful opportunity to meet Dharma friends from all over the world and feel a part of the ancient tradition that was founded by Buddha 2500 years ago.
Here is a couple interesting links with some pictures of the Vesak 2008 Celebration.