I've always used the Bus Eireann when i've gone back home. Used to stop off at a few places so good chance to stretch your legs and meet a few people.
You could try the Cnoc Suain Village to see traditional Irish villages, hire a bike and go cycling around Connemara. You could always get a rod licence and try your hand at a spot of fishing also. Not been to the city for a long time, but i'm told it's still got enough to keep you busy for a few days, lots of decent pubs for a beer on the night (Cookes Thatch Pub is one i remember).