Well, although there are many ways to play out a scavenger hunt, it is basically a game where clues are prepared that hint at specific items, the players then use these clues to collect all the other clues/items on the scavenger hunt list. Sometimes this is then combined with specific task, like with photo scavenger hunts, where players must take photographs of all the items on the list in any specific order.
The winner/winning team is usually the first to complete the entire hunt or have all the clues of the list. To add interest, players/teams may also be set the challenge of completing special tasks or trails between each clue.
Although predominantly in the real world, there are also online (internet) treasure hunts, musical scavenger hunts, fact finding hunts, and many other great twists on the traditional hunt.
To make it more exciting, organizers will normally offer prizes, such as sweets, money, toys or gifts for the team/individual that solves all the puzzles first and wins the treasure hunt.
Scavenger Hunts and Treasure Hunts are pretty similar. Although there are many different understandings, I believe that the scavenger hunt offers prizes along the trial, like chocolate eggs and candy, where are the Treasure Hunt offers a main prize at the end of the adventure, just like with a pirates treasure map.