That actually would be pretty cool. That when I press the attendant button, the FA would call me back to see what I want instead to coming over then have to go back and return with a glass of water.

The possibilities are endless:
Meal selection by telephone
Vote on continental idol via telephone.
Who wants to be a continental millionaire and use the pax for one of the lifelines
For AC w/o individual AVOD have pax vote on movie
If you have a continuing CO flight, you might be able to check flight status via telephone. Have it continually beamed up and updated, and I could check status by typing in my flight number