If in Limerick please take the time to go 15 mile out the Dublin Road to Killaloe. One warning is that since the tiger has taken effect the place is awash with trendy city types, which takes the gloss of an otherwise cracking place.
The town sits nicely on the shores of loch derg and offers great water sport activities. Alternativley drive a little outside the town to a pub called the 'Pigeons Rest' and indulge in the nicest pub grub in limerick. Be aware of the goat as he bites.
My tip would be after a good fill of Guinness or what ever your tipple may be is to head for the shores and soak in the beauty of your surroundings. May is a goos time to go as you may get a good day and not have to deal with the crowds.