mndlbrt
onekb.net offers ultra cheap hosting... if you can fit your stuff into 1024 bytes!
I decided to write a mandelbrot renderer in 1kb. mndlbrt is the result! You can zoom and even share the current image with others (the URL automtaically updates to represent the current area). Also learned a bit about the HTML canvas in the process, which has a surprisingly sane API for webstandards.