Microsoft has made Silverlight 5 available for download.
Here are some of the developer related enhancements:
XAML Debugging with breakpoints for binding debugging
Implicit data templates for easy UI reuse
Double (and multi) click support
GPU-accelerated XNA-compatible 3D and immediate-mode 2D API
Low-latency sound effects and WAV support
Real operating system windows and multi-display support
Significant performance improvements, fixes and much more
Take a look at the Windows 8 Win RT image…see SilverLight anywhere?
Silverlight also doesn’t run in the browser on mobile platforms, Adobe announced a couple of weeks ago that they are stopping developing Flash for mobile platforms as well…yes Steve Jobs is laughing from his grave. IE 10 on the Metro version of Windows 8 does not support plugins, this means no Flash or Silverlight
Either way, you can download Silverlight 5 here: http://www.microsoft.com/silverlight/ it might be the last version that you will download