What can you never eat for breakfast? The answer - found by John K. - is : Lunch or dinner!!!
A doctor had an urgent call. - Can you come immediately, doctor? My son has just swallowed a fountain pen. - I'll be there right away. What are you doing in the meantime? - Oh, I'm using a pencil.
(urgent call = επείγον τηλεφώνημα, swallow = καταπίνω, in the meantime = στο μεταξύ)