Silverlight on WSUS
http://blogs.technet.com/wsus/archive/2008/10/21/silverlight-now-available.aspx
On your WSUS tonight is Silverlight 2.0.
For those that consider Java evil, Flash even more evil, consider that Silverlight is the less evil one. But regardless, until there is an overwhelming need to run an application, you can simply not approve the update.
Read the complete post at http://msmvps.com/blogs/bradley/archive/2008/10/20/silverlight-on-wsus.aspx