Accelerometer - MMA8451 module from Adafruit
Warning - This does not work with the new Raspberry Pi. It uses some hoary old 'repeat start' for the I2C. The AXDL345 works perfectly, and I'm going with that for now.
Many, many hours trying to get this to work, and I never found anybody with success. I certainly didn't have it. Oh well, I learned a lot. :)
ps. the adxl345 module is incredibly cheap direct from China, but I have to wait a month. Oh well, cheap is best!