Take the DART in Dublin and get off on a random station. That’s what me and my two friends did last Sunday.
We didn’t know that Killiney was home of a 150 metres high hill over a long shingle beach. On our way up, we also discovered a number of luxurious 3-storey houses with beautiful gardens and people playing badminton.
It’s a good option if you don’t want to go too far from home on a Sunday. Just get off the train, place your sheet on the pebbles or walk to the top of the hill and enjoy!