The Liquid Rescale Tool, also known as the Content Aware Scale Tool on Photoshop, basically fucks up pictures by resizing them to any resolution you like, but it also keeps the most "important" features the same size as the original. This means that it can make images look like "animu" and "Woll Smoth" (but not at the same time), which obviously has massive potential. Download the GIMP version here.
Some "Animu" examples from Something Awful
...ond somm from tho othor woy roond (stoll from Somthong Owfol)
You can also make animated .gifs from them by doing the effect as normal, resizing the result to its original size, then repeating it over and over and making each result a frame:
And finally, a few of my own:
Jodg Orsholl (from Ponk Floyd's Tho Woll)
On Tho Court Of Tho Cromson Kong
(no templates/exploitables, just grab your image off Google Images and use the plugin)