Audio signals such as the announcement “You have mail,” can redirect a user’s attentions away from a current task. In the context of computer use, name other situations where sound successfully attracts attention without overly aggravating the user.

What will be an ideal response?

The following are possibilities:
A beep announcing the finish of a long download.
A beep announcing that a person you want to talk to is ready to begin an on-line chat.
A beep reminding you of a meeting you need to attend.