My current latest hobby project so far is GigaFFT. 16 GBytes FFT transformed out of core in 200 lines of C# on ordinary home computer.
I also have electronics hobby. Interested in astronomy, diets, homebrew computers, small time hacking like JTAG access to BeagleBone ARM hardware in C#. Microframework. Pixel drawing using parallax chip, Netduino, 8 bit Atmel, etc.