This is a very simple CQRS sample I've used in a few talks. There's a Framework.cs class that has an entire cqrs "framework" in it.
If you want to use it in an app, simply add the file and add a NuGet reference to RavenDb. I've used the embedded version here.
The framework is pretty basic but does event sourcing and has built in concurrency checking. 
The application code is garbage, nothing has tests but there is a point - notice how everything is independent and can be improved to use whatever flashy greatness you want.
No industry standard message queue, no IoC container - yet we have flexible extensible code.

You can literally take the single file framework and start coding domain logic for almost any application. Once you've got something stable
and know you need a feature (caching, sharding etc.), you can literally plug that in. Less up front set up - more up front code enabling us to fail faster.
Enjoy!