I was demoing my Slide Rule to a guy at work yesterday and came across a Force Close. It turns out that my app has a memory leak in it. To replicate: go from landscape to portait and back again several times. Eventually, the app will crash because it runs out of memory.
So, over the lunch hour I read up on handling memory leaks and detecting them. Turns out you can use the Heap profile in DDMS. I'll post details after work today. Hopefully I can get this problem cleaned up tonight and return to my libgdx & OpenGL ES studies.