I am in the infancy of my career as a Windows driver developer. This has given me experience in both C and C++ and Kernel-level work (The kind of stuff that causes the lovely Blue Screen of Death).
I recently coded and released an application on the Android market called BestSignal (also available on Amazon). This has been invaluable experience and I tend to not only improve that application, but work on others as well.
I have also coded a few side projects that were intended to teach me other languages and solve simple problems of my own (I have a nice budget program that works perfectly for my needs).