Share 'Where to go in Northern Ireland?'

Hi there,   My girlfriend and i are planning to visit Northern Ireland in August. We booked a b&b in Coleraine.   We really like historic and monastic sites, Celtic crosses, ogham stones and so on. We assumed that the North would be filled with them, but apart from a few castles, i can't find a lot on the internet. Do you have any tips?   O, and tips about irish music sessions are welcome as…