Did you know you can measure your heart rate with your Android phone? Here's how:
Step 1: From the Android Market, find and install Instant Heart Rate.
Step 2: Launch the app and gently place the tip of your index finger on your Android phone's camera lens. Give the app a couple of seconds to calibrate and it will begin measuring your heart rate.

Step 3: After about 10 seconds, your heart rate will display on the screen.
To try again, tap the Measure button on the screen.
That's it. Now you can take your heart rate anytime, anyplace. Just as a note, the app was within 1 BPM of a Garmin Forerunner 305, which included a chest strap heart rate monitor.