Museumr lets you portray your favourite photo in a Museum setting as shown here.
The Jigsaw Puzzle option divides the photo into jigsaw pieces - which if you were really dedicated, you could print and cut up to produce a 'real' jigsaw puzzle. The Sketch Tool produces a realistic drawn representation of your photo.
Depending on your photo, the Easter Egg creator can produce some lovely effects:
Another interesting site is Photojojo which provides a twice weekly newsletter on photo tips, project ideas and news about interesting photo websites.
There are also many more fun tools at Fd's Flicker Toys including badge, calendar, CD cover and poster makers.
Technorati Tags: dumpr, flickr toys, photo, photojojo