The first option you have is, of course, to learn more about CUDA and General-Purpose GPU (GPGPU) programming in particular. In this case, you have probably already found a good application of this and want to write even more advanced or optimized CUDA code. You may find it interesting for its own sake, or perhaps you want to get a job as a CUDA/GPU programmer. With a strong GPU programming foundation in place (which was provided by this book), we will now look at some of the advanced topics in this field that we are now prepared to learn about.
Furthering your knowledge of CUDA and GPGPU programming
Multi-GPU systems
The first major topic that comes to mind would be to learn how to program systems with more than one GPU installed...