Getting a taxi
Taxis are easy to come by as long there are at least two of you looking for one, but you could be waiting for a while on your own. Taxi ranks are in St Stephen's green, College Green but there is a vast queue/line of people in looking for a arm chair ride home! Some places like Q bar, Pravda & Zanibar are right beside the ranks (2 minute stagger) in O'Connell Street (Stef).
Northside taxi ranks are generally less busy than southside, so it's worth the walk across the river if it's busy southside. It's also possible to take the DART from the city centre at night. The last trains leave Connolly/Tara Street/Pearse stations from about 2315 - 2330 (editor).