katieboo, before answering your question I would like to give you a word of friendly advice for posting to this board. Please turn off your caps lock when posting a message. All caps are perceived as yelling on the internet, also it's harder to read.

I spent only one day in Dublin, but I did enjoy the hop-on, hop off bus tour. It's a great way to get a good overview of the sites on your first day in town. You can get off the bus at any of these sites, then pick up the tour right where it left off. I'm sure that others will come through with more ideas. Have a good trip.

Trinity College - Book of Kells
Dublin Castle
Ntional Museum of Archeology & History (so many people forget that Ireland was one of the very few lights of civilization remaining as Rome fell and the Dark Ages engulfed most of europe)
Dublinia
Shop Grafton St
Have a drink at Temple Bar
A theater performance - preferably an Irish author (Shaw, Wilde etc)

If you look above under desinations you'll see dozens of other recos.

The hop-on, hop-off bus tour is a great suggestion - you should see quite a bit that way. Trinity College, The Guinness Storehouse, Grafton Street, Christchurch Cathedral, etc are all worth visiting.

Also, you should take a look at http://www.stpatricksday.ie/cms/home.html - there will be lots of information on "what's on" around the city that weekend.

www.visitdublin.com should help.

Kilmainham Gaol is a MUST! All who have been there RAVE about the tour.

Also, you will love the Zozimus Ghost Tour!

www.zozimus.com