We enjoyed delicious food, travel a lot by metro and tram, we enjoyed Zappeio and spent a lot of time in the city center (Plaka, Monastiraki, etc.) and also in near neighbourhood with our 2,5 year old daughter.
There is a great caffeteria near house, where older Athenians sit and drink coffe and enjoy life, we liked it here a lot cause we like that atmosphere.
People are very nice.
Also trip to Sounion was perfect, the see is so warm and wonderful here.
Little one also enjoyed a museum, cats everywhere and of course bakeries.
Athens is always good idea. :)