The money app is gaming, but check out the personal infrastructure angle.

“Ritter also described how he added a cool P5 data glove that can be used to control a mouse pointer on a PC. The glove had to be customized to work with the Sun SPOT: Ritter added two perpendicular gyroscopes, and then the Sun SPOT was attached to the back of the glove using velcro. In Ritter’s experience, a refresh rate of 1/25 sec is optimal for smooth mouse movement. However he also confirmed that the data glove is not yet a viable replacement for a mouse since it needs to be calibrated for each user.”

http://java.sun.com/javaone/sf/2007/articles/robotics.jsp