The Irish History Walking Tour is led by Trinity College graduates who majored in history. One feature of the tour is their willingness to debate any historical point. Supposedly, they can opppose you and convince you and the rest of the tour you're wrong. Then they can take your point, which they've just proved wrong, and convince everyone you were right. This didn't happen when we went. Our group was either very polite or lacked any understanding of Irish history... possibly both. At least that was true for me.
There's a lot of ground to cover: Dublin's founding by Vikings in the 9th century, the Anglo Norman invasion in the 1100's, the Catholic-Protestant split following Henry VIII's break with the Pope,the potato's role in Ireland, the struggle for independence and today's political situation. It all plays out while walking from Trinity College, the Bank of Ireland and City Hall to Dublin Castle and Temple Bar.
The downside: ours was a 2 hour 15 minute walk and, no matter how interesting, my feet were sore!
But it did a couple of things: it put a lot of Irish history into perspective and made our later visits to the National Museum and historical sites around the country more meaningful. It sparked an interest that has me tracking down books on Irish history from my local library. Maybe on my next trip I'll be prepared well enough to get into an argument about some obscure historical trivia!