U BuddyPress Forum Editor plugin by taehan has the ability to convert HTML TEXTAREA fields to TinyMCE for BuddyPress Forum. Several options are provided, such as customizing button group, form validation, etc.
BuddyPress is an open source social networking software package. It is a plugin that can be installed on WordPress to transform it into a social network platform. BuddyPress is designed to allow schools, companies, sports teams or any other niche community to start their own social network or communication tool.
Download and info: http://wordpress.org/extend/plugins/u-buddypress-forum-editor/