BuddyPress.org

open up style.css, you need to modify the header (i.e. this section)

/*

Theme Name: BuddyPress Default Home Theme

Theme URI: http://buddypress.com/

Description: A widget framework theme for the home of a BuddyPress enabled installation. This theme is not required to use BuddyPress.

Version: 1.0

Author: Andy Peatling

Author URI: http://apeatling.wordpress.com

*/