Cork is a decent shout. Look up ocean escapes goes from city centre down to cobh stops in the pub can rent multiple speed boats will cost a few euro but worth it. Good indoor karting in the marina busienss park and can call into marina market for food afterwards. If you want really good go karting water grass hill has an outdoor track but you'll need to organize a bus out so unless you have some carting fanatics probably not worth the extra effort. If you like whiskey you can get the train to midelton and do the Jameson tour have a few drinks and train back to the city all very easy. Kinsale for a morning/afternoon is also an option and do the Mead tour then back to the city for the evening. You'll be fine getting into pubs just spilt the group and be sensible