This is your resource to discuss support topics with your peers, and learn from each other.
Is there a way for a background application to play a .wav file when the BlackBerry is inactive (not being used at the moment) or is in the holster?
I'm not usre it will work if password protected, but you can use the Sensor class on 4.6+. I can't remeber what the class/listener is for previous OSes at the moment.
What about just playing a .wav file?
If it's too complicated or not possible, can I make it beep?
Use the listener to check for the desired condition then just play the audio file or the alert.