Staying on and seeing more of Athens after Trust in Play

I’m planning to stay on in Athens for a couple of days after TiP. BTW, if anybody else is around, all of Athen’s sights and museums are free on the Sunday apparently…also I’m thinking of taking a ferry out to Hydra on the Monday. I’m happy to hook up with other playful people if you are also out and about exploring, so let me know if you’d like to see similar places - or have other recommendations. cheers, Bronwin