An old mate came to visit recently and he brought the bell for me as a gift....
....and, it is something I have always wanted, not that he knew that, but clearly
he knows me well.
My son (10) spends most of his time upstairs in his room racing F1 sim, but we
have trained him to respond to the bell for lunch, dinner, visitors and general 'we need
you downstairs' stuff. It works well.