Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover. -- Mark Twain
Often, I just want to travel. Just get away. Go some where new. If the price is good and I’m free, I’ll go. I don’t even really care where. For people like me, here are some websites that allow you to do that.
AirWander suggests multi-day layovers that reduce your ticket price after you've given your departure and final destinations.
If you need to travel and want to explore another city as a stop-gap while getting a lower airfare, you need to use this! Choose your departure and arrival cities and your travel date, and it will recommend places with the price savings. You can also modify how long you'd like to stop over for. It's a wonderful way to break down a long trip while being offered a chance to see somewhere new for cheap. http://airwander.com
Adioso is a website for adventurous travelers who want to take vacations and are flexible on days or even places.
Adioso allows you to search flights with complete flexibility, like if you want to go somewhere in Europe in November but are not committed to specific area or time. Examples of the natural language-enabled broad or open-ended searches specific to Adioso:
Chicago to Boston next week
San Francisco to Europe late September under $800
German Wings Blind Bookings allows you to buy a flight and find out where you’re going on that day.
Surprise flights at guaranteed fares!Simply select your departure airport and the type of holiday you want by clicking on “Party”, “Snow and Skiing”, “Shopping”, “Christmas Markets”, “Metropolis Eastern Europe”, “Metropolis Western Europe” and “Culture”.
Kayak has a site called Explore that lets you see where to travel to for a given price on a map
Google Flights has a function that lets you explore destinations based on interests, rough dates, and general locations
German Wings seems to be the only operator that truly has secret flights that you book but don't know where you'll be going until after. Still most of the websites above will inspire you and recommend places to go with very little information from you.