If you’re deploying Active Directory Federation Services 2.0 in your institution to enable single sign-on you might want to customize the default look and feel with some custom text, logos and colours to make it fit in with your brand and to make it more familiar to your users.
Or just something different from the norm:
Helpfully, there are some places you can go to find how to do this:
How have you themed yours?
Have you changed your sign-in page to look different? Show us in the comments!