Dooley Vacations An offshoot of Dooley Car Rentals. First night is prebooked. Also Great Britain and France. 877/331-9301, dooleyvacations.com.
EuropeASAP You won't know the airline or the exact departure date until after you book (enter two possible dates and you're guaranteed to get one). Also Great Britain and France. 415/750-5449, europeasap.com.
Ireland.com Ireland packages only. Unless you request otherwise, your first night is prebooked in a hotel near the airport. 800/896-4600, ireland.com/travel.
Sceptre Tours Ireland only. First night is prebooked unless you request otherwise. 800/221-0924, sceptretours.com.
From drive-up volcanoes in Hawaii to the ones that once toppled entire civilizations in Italy and Greece, you won't want to miss these visitor-friendly volcanoes and the chance to hike up--or inside--these magnificent forces of nature.