David Hewlett battles the Yeren!
There are at least seven photos of Stargate Atlantis' David Hewlett working as director (and clowning around) at this Flickr page - http://www.flickr.com/photos/craige17/

This is one of the goofier ones posted.
Thanks to
simboo for the tip! And for 'Gler' for posting them! No copyright infringement meant or intended by reposting the picture.

This is one of the goofier ones posted.
Thanks to