mediaqueri.es
Media Queries showcases some lovely responsive web sites, showing at a glance what they would look like at four different sizes (smart phone, tablet, laptop, desktop).

liquidapsive.com
Liquidapsive (Liqui-dap-sive) shows how the same web page responds to a changing browser size when produced using Adaptive. Liquid, Responsive, and Static layout. We’ll be building responsive web sites (layouts) in this class. We can’t cover all the UX issues.