See blog post: http://blog.alexandre.berthaud.me/posts/2013-04-25-using-a-raspberry-pi-as-an-alarm-clock-with-mpd.html

alarm.sh

#!/bin/bash
SLEEP=`echo "$1*3600" | bc`
echo "Alarm triggered in $1 hours"
sleep $SLEEP > /dev/null
echo "Starting playing"
mpc volume 50 > /dev/null
mpc play > /dev/null
mpcfade.sh 50 65 0
mpcfade.sh 65 75 1
echo "Turning on TV and switching input to me"
(echo "as" | cec-client -s -d 5) &
mpcfade.sh 75 82 2
mpcfade.sh 82 90 4
echo "Full volume, have a good day!"

mpcfade.sh

#!/bin/bash
VOL=$1
TO=$2
SLEEP=$3
echo "Fading from $VOL% to $TO% (step: $SLEEP second(s))"
mpc volume $VOL > /dev/null
if [ $VOL -lt $TO ]
then
  while [ $VOL -lt $TO ]
  do
    sleep $SLEEP > /dev/null
    VOL=$[$VOL+1]
    mpc volume $VOL > /dev/null
  done
else
  while [ $VOL -gt $TO ]
  do
    sleep $SLEEP > /dev/null
    VOL=$[$VOL-1]
    mpc volume $VOL > /dev/null
  done
fi