well, for something more unusual give this okay if you are passing near Brno -

The Punkva Caves:-
Visitors walk through the labyrinth of mighty underground spaces and corridors as far as the bottom of the world-famous Macocha Abyss. The foot walk is followed by a motorboat ride along the Punkva underground river. The ride includes the visit to the Masaryk Dome, one of the most beautiful caves of the Moravian Karst.

How about the underground boat ride at Rocamadour, where the guides like to stop the boats at the deepest point and rock them like crazy to scare the passengers? Actually, as far as a boat ride goes, it's not that impressive.

I love the gabarres on the Dordogne. And I used to enjoy kayaking down it, too, until our unfortunate little escapade in August.

Years ago I took several Rhine and Danube boat excursions and loved them. Must get back there!

But my best boat excursion ever was crossing the Isthmus of Somethingorother between Ephesus and Samos at night on a small boat under a full moon. The captain caught octopus while we rode and grilled them on a hibachi, and we ate them and drank little glasses of raki - delicious!

In Ireland I enjoyed a boat ride to the Skellig Rock which is about 8 miles off the coast of Co. Kerry When you get off you climb 600 feet to where monastery buildings abandoned 1000 years ago still look good.This trip should only be done on a fine day as the boats are small.Interesting too was the trip along the base of the Cliffs of Moher from Doolin,a trip to see dolphins from Carrigaholt and the trip from Dingle along the coast.I really enjoyed the trip through the 3 Lakes of Killarney too.