Chevereto is an open-source image hosting script that could easily be used to create a service like ImageShack or TinyPic (providing you have a good server) or a smaller personal operation.
You can see a demo of the script here.
It looks pretty nice at a glance, and it could potentially be useful for a lot of people. If you hacked it a bit to require a logon to upload, it would make a nice personal image uploader for images you wish to hotlink somewhere else, such as forum signatures, photos in blog entries, etc.
I rather like the idea of a personal image host, though I don’t know what exactly I would do with one…