Approximately a year ago I used a search engine for flights that allowed me to compare flexible dates and flexible destinations and presented it all neatly on a line graph. In other words, I wasn't sure where I wanted to go, so I entered a destination and approximate timeframe and had the ability to add destinations to the graph. I believe it was through bing, but now I can't find it. Any ideas? Needless to say this would be really handy to decide where to go to for my next trip.