Here's an idea that combines Doctor Who fandom with Google's new Search-By-Image feature.

Start with a photo of yourself. That is your first incarnation as a Time Lord. Now feed that image into Google Seach-By-Image and choose one of the images it thinks are similar (first page only, if there's more than one page). That is your second incarnation.

Iterate. Feed each image you select into Search-By-Image and select one of the results to be your next incarnation. Stop when you've got 13 pictures all together including the first. Oh, and you can change gender as much as you like.

Here are my 13 incarnations:

1. http://outerhoard.files.wordpress.co...newglasses.jpg
2. http://www.kuleuven.be/wieiswie/nl/p...00060453/photo
3. http://papilot3.mykmyk.pl/img/660/0/papilotka.jpg
4. http://www.bigislandchronicle.com/wp...11/05/zach.jpg
5. http://lh5.ggpht.com/_FcPmHZ1IllY/TK...2/IMGP3454.JPG
6. http://www.makemeuprenee.com/wp-cont...MG_3597ret.jpg
7. http://www.voxpilot.com/image/image_...=1306142737131
8. http://www.beauty-make-up.net/bilder/0037-01-1.JPG
9. http://club.itdrom.com/files/person_...0287090165.jpg
10. http://i43.tinypic.com/r0nqz4.jpg
11. http://i.cdn.turner.com/dr/teg/tsg/r...24081mugs5.jpg
12. http://www.kuleuven.be/wieiswie/nl/p...00073015/photo
13. http://1.bp.blogspot.com/_4CLbOw32sX...0/IMG_0076.JPG