Derick Rethans has posted his own look back at all of the happenings that went on back in 2005.
Welcome to the fourth installment of the PHP Look Back. Just as in previous years, we'll look back on PHP development discussions, bloopers and accomplishments of the last year. This is not supposed to be a fully objective review of last year--note that the opinions in this article are that of the author, and not of the PHP development team.
He covers each month, giving the happenings for each month, linking to various posts and items in each one. Most of the things discussed are more related to the internal PHP development and discusssions from the mailing lists.