Photo via MuggleNet
Dan Radcliffe created this card to send to fans who wrote to him during the 2004 holiday season. The picture was taken in the water tank used in filming the underwater scenes in Harry Potter and the Goblet of Fire; the antlers and red noses were Photoshopped in later by Mr. Radcliffe himself. It's worth taking a look at a larger version of this picture (such as this one at mugglenet.com) to study the details; Robert Pattinson and Stanislav Ianevski are both in there, as are their (and Dan's) stunt doubles. Clémence Poésy doesn't appear to be in the picture; the woman in front is, I think, her stunt double. Also, check out the guy on his knees on the the far left, who is almost certainly an ancestor of Miles O'Brien, and the woman (?) at top left making a rude gesture.