Well, I'm sure broadcastjunkie will slam me for getting off topic, but I might suggest this: If you get up at the same time on certain days, you can always use Tasker to play a song or make a noise based on a calendar entry. This is what I use for my morning alarms. When I know I'm not going to need to wake up to an alarm on a given day, I simply delete that day's calendar entry in Google, then I don't have to worry about turning the alarm back on after the day I skip. Works well for me. SVOX's UK English Victoria wakes me up every morning with a custom message.