You've probably heard of Orleans as the open-source framework Microsoft uses to build cloud-scale services for products, such as Halo and Azure. But how do you use it effectively in your own applications? In this architecture talk, John & Sergey discuss several challenges that you will face when building cloud services; introduce several proven, powerful design patterns & practices such as state-machines, smart-caches, and event-sourcing; and some anti-patterns to avoid.