For less than $100 you too can whip together a pocket cam rig to film test users of your mobile app and spot trouble areas. From the Artefact blog:

Staring over your participant’s shoulder isn’t creating the most natural situation when testing user experiences. You get less than ideal viewing angles, participants can’t get into a flow and it’s hard to get good video of it all. So how do you get around that? I’ll introduce to you a few key pieces of hardware and software that can make your life a little easier. Maybe even the coolest researcher in your department, in less than an hour.

Cheap POV video for mobile phone studies