For a great view of the city (especially at night) go to the top of the Eiffel Tower at Paris. It also offers a great vantage point for viewing the water show at the Bellagio.

cdm115 Article on Las Vegas Casinos

A hike to the top of Yosemite Falls is among the best the park has to offer.

ankopsu Article on Yosemite National Park

I dont think anyone has ever said they didnt enjoy George's boat! Its by far the best optional on tour! The water is amazing and George is quite the entertainer ;)

Steftacular Article on George's Boat, Corfu