It’s pretty rare that I will plug a particular part, but this is also a pretty exceptional part.
I recently came across an Analog Devices part, the ADXL330. I think this part is going to change the world. It is a 3-axis accelerometer in a 16-pin leadless flat chip scale package, and it is darn simple to use: it basically translates acceleration into a proportional voltage. The best part about it is it’s darn cheap too, at $5.45/1ku budgetary pricing. Almost anything can have a 3-axis accelerometer in it now, at that price.
It also has pretty good performance for a MEMs based accelerometer–you wouldn’t use it to guide missiles–but it’s definitely good enough to enable any number of interesting and innovative applications. I love the part so much I’m designing it into the next generation chumby. The user interface implications for a 3-axis accelerometer are really astounding.