Powerscourt House and Gardens
Take the 44 bus from Townsend St down to Enniskerry and you can either get the Alpine coach up to the gardens or to the waterfall, or you can walk to the gardens (the waterfall is quite far and up a very narrow raod). There is an entrance fee, and I suggest not bothering with seeing the house..it was gutted during a fire and renovated but with spare furnishings. Spend your time in the gardens - which include a gorgeous Japanese garden retreat, the Italian gardens in front of the house (featured in the movie The Count de Monte Cristo recently), walled gardens, a pet cemetry, a faux-round tower you can go up and stunning trees and shrubbery. Enchanting.
Great place to visit if you have a car or if you can get a lift from friends. If you are going to the shops or to the Garden Center do not pay in at the Gate it is free!! If while you are there you want to visit the gardens or Waterfall you can pay later on at the house. Just say you are going to the shops when you check in at the gate. There is enough to see in the house & garden center to take up about 2 hours. Then there is the wonderful cafe/ restaurant to relax in afterwards while you enjoy the spectacular view of the gardens. Good for either a sunny or a rainey day!
Taking the 44C bus route from the city centre will provide you with a nice day out of the city. The bus journey takes approx 1 hour and finally leaves you in the pretty town of Enniskerry. Along the way you will encounter brightly painted pubs, little stone churches not to mention the rolling green countryside and mountains. My tip is to sit at the front on the upper deck of the bus to get the best views.