If you're in need of inspiration because your vacation scheming never got more specific than 'I need to get out of here,' take a look at Atlas Obscura.
Atlas Obscura is an online catalogue of the strangest sites the world has to offer. They're even working on organizing tours some time in the near future for the people on their mailing list. You can search for curious sites by category, continent, and country (as well as by state in the US); but if you've got some free time on your hands (and if you're here you clearly do) then try just clicking around on their map. The sites cataloged range from a Plague museum in the Netherlands to the world's largest drain with just about everything in between. The Atlas staff also gives readers the chance to suggest new sites to be added to their ever-growing archives.
Once you've decided where you want to go the next questions are how to get there and where to stay. This is where Travel Zoo comes in.
Travel Zoo isn't too flashy, but they've got some of the best travel deals out there. Plus you can sign up for their weekly email of the Top 20 best deals they have going right then. You can even search for places to visit based on the kind of trip you want to take. For example if you're looking for ideas for a ski weekend or a romantic getaway (or a romantic ski weekend, perhaps?) they've got you covered. Travel Zoo makes the entire reservation process mercifully simple and painless which I think everyone can live with.
If you find yourself heading to Europe to go backpacking all over the continent and need some short, cheap flights while you're there, check out attitude Travel. It's a complete index of all of Europe's low fare airlines categorized by price as well as by the regions and countries in which they're active. It even extends out of Europe and into North Africa, Turkey, and the Middle East. The site is amazingly helpful but take some advice from Coda: don't make any reservations that depend on making tight connections, on trains or planes. If there's anything I've learned about Europe it's that time is a very fluid concept and getting hung up on details like 'on time arrivals' and 'making your next flight' will only bring frustration.
Now all that's left is packing...but we can't help you there.