Metronebble - a Metronome for Pebble
More details (and a binary) available at http://seb.so/pebble/metronebble
Press the select button (middle) to enter "sampling" mode - tap the pebble to set your tempo. Then press select again to get it to pulse at the tempo you've set. You can also increase/decrease the tempo with the up/down buttons.
To build, make sure you've got the Pebble SDK 2.0 setup and working, then just run make or if you've setup PEBBLE_PHONE environment variable, make install