Interested in archeological Roman ruins there are a few scattered about through the region with the most notable being the ruins in the city of Aquileia. This site has some of most important Roman artifacts as well as early Christian remains in Italy.
There are also more than a half dozen castles in the region some of which are medieval in nature and some are more modern being built in nineteenth century. The most notable castles to see are the castle Miramare and the Castello di Duino both of which are built on the edge of the cliffs overlooking the sea.
After you are finished looking at the Roman ruins and castles there is plenty to do in the regions towns with over 60 museums and galleries to see ranging from ancient art and archeology to modern and impressionistic art. If you want information about a specific museum you should do a search but because so many towns have a museum they call the civic museum you should include the name of the town it is listed under.
There is also plenty of fabulous Italian food to try throughout the region in a wide variety of restaurants ranging from mom and pop places to fine dining establishments.
The real jewel of the region like so many of the other northern regions is its outdoor activities which includes hiking trails, mountain biking and rock climbing to keep you busy in the summer. Then in the winter there are over 40 ski areas to choose from with skiing, snowboarding and cross country skiing available making the region a summer and winter playground.