If you frequently travel, that likely means you also frequently try to find the best flight deals. I often use Matrix, or Hipmunk when looking for cheap flights. While these sites have computers aggregating from many different sources, I just came across Flightfox, a website where you offer a commission (minimum $19) to create a contest for humans to find you the best flight deal!
If you think you can find a better deal than your peers, take a look at their existing contests and suggest a better deal! Here's an example of someone who made $500 finding the cheapest trip across 6 continents.
UPDATE: September 24th: The reddit travel sidebar thread
UPDATE: Nov 2, 2018: Skiplagged (Thanks Laura F!)