Windows Presentation Foundation / Everywhere
Microsoft is coming out with what many call the flash killer. The code name for the new software is WPF/e. WPF/e is a stripped down version of WPF which does not include any 3D support. The initial goal of Microsoft is to keep the download down to 1-1.5MB. You can listen to some recent podcasts/videos on this new technology here and here. Check out this cool Flash and WPF/e interaction using JavaScript.