In reply to Jeff Chandler.

That is a very good question. You can probably replace the present Thank a Plugin Author Day, since it may have gained a bit of momentum or those with better knowledge of WordPress history could suggest a notable day in it's history, like the millionth download, or when the 100th contributor joined something like that to help point out the significance of WP to it's users.

Maybe you can write a post or run a poll asking for more feedback on it and also ask other well known community members or some of the founders for their feedback on the best way to make it happen and have an impact.