What better way to spend time than experimenting with code for an OpenGL shader - now you don't even need a desktop machine as ShaderToy works on your Android phone.
If you are a geek then you probably own an Android unless you are a stylish geek when you probably own an iPhone. If you have made a mistake and don't have an Android then there really is a good programmer reason to get one - ShaderToy.
ShaderToy lets you edit OpenGL ES 2.0 shaders directly on your Android (2.2 needed). Your phone also needs OpenGL ES 2 hardware and the notes suggest that to make writing the code easier a keyboard (real) might be a good idea. It has also only been tested on a limited range of devices (two) but it should work with standard hardware.
ShaderToy is created by Industrial Arithmetic (love the name) and is inspired Inigo Quilez's ShaderToy which works in a WebGL capable browser.
You can download it for free (its in the app market) and start coding shaders or just trying out the samples at once. At the moment it doesn't have a save option but you can copy and paste the shader code into a notepad to use in other applications.
At last a programmer's app....
ShaderToy for Android
Other relevant articles:
Custom Bitmap Effects - HLSL
Thanks to: http://www.geeks3d.com