Remembering my late 1600s history of Ireland (and in between events), I of course remembered a certain siege. The castle is still there (alright, there has been a bit of rebuilding since the heavy bombardment during the second siege!) and a fantastic Nine Years War section with videos, uniforms and interactives. It was refurbished in 2012 with the new museum part added.
Originally a wooden structure, and existing through the medieval period, the castle gained notoriety during the sieges that occurred during the Williamite wars in 1690 and 1691.
Colonel Grace's refusal to surrender to General Douglas, a desperate bridge battle (Donnybrook - I'm looking at you for re-enactment rules) and a massive bombardment during the second siege are all notable events. There is plenty of fodder here for suitable scenarios.
Would certainly recommend a visit if you're in Ireland. A great slice of late C17th history too.