Ooh! I had the time to modernize the online version of The Rasterbator, which, sadly had been offline for over half a year.
The online version has, I think, quite nice user experience including lots of Ajax and drag and drop file upload. Although it is quite a small detail, I'm quite proud of the human silhouette that indicates the poster size.
Coders would probably be interested that it is based on ASP.NET MVC 4, jQuery (with some plugins) and iTextSharp.