This plugin adds hovercards (like on WordPress,com (Gravatar), Twitter, Facebook, Google+, etc.) to BuddyPress. Whenever a user hovers over a user avatar, the hovercard shows up.
Hovercards are completely themable by adding a hovercard.php template to your (child) theme.
Based on imath’s blogpost on BuddyPress xprofile hovercards and uses the jQuery Tipsy library and Rrrene’s hovercards.