I occasionally use Amphetadesk at work. It’s an RSS aggregator, which loosely means that it scans a bunch of web sites and presents summaries of them to you. Amphetadesk has an interesting approach in that it creates a local webserver that your browser connects to. Since it’s just a web server that serves HTML pages, it doesn’t have to change its GUI for each OS and thus theoretically works equally well on any operating system. At the least, it’s an alternative to Java.