I had this simple idea a few years ago after my kids got excited about finding treasure and solving clues (no doubt the result of a movie they had watched).
As my sons birthday was coming up I decided to set up a little treasure hunt just for him. Needless to say my kids had a blast solving the clues, and finding the treasure. Since then it has been one of the most requested games they want me to play with them. And here's how it works.
First: Figure out what your kids are going to discover when they reach the "treasure", and where that prize will be located. For example lets say I bought my son a new book I would start by placing it under his bed (he'll never think to look there).
Second: Create clues working backwards from the "treasure". For example if the treasure is under my sons bed I create a clue that leads to his bed. I then create another clue that leads to the location where I am going to hide the bed clue (maybe the refrigerator...). I then continue making these clues until I have 10-12 of them.
Third: Take your stack of clues and place them in their respective hiding places. The first clue will be unhidden as you will give it to your child as the first clue, which will lead to the second and so on.
Below are a few examples, and a simple walkthrough.
Let's say this is the first clue I hand my son. This is an example of a picture addition clue. Hopefully he will quickly figure out that it is a dog house, and head to our dog house for the next clue.
When my son searches the dog house he will find this next clue. This one is a translation challenge. My sons speak Spanish at an intermediate level, but if I throw in a word they don't know it creates a little bit of a challenge. Once they get out their spanish dictionary and figure out that this means asparagus they will hopefully head to the refrigerator.
Searching the refrigerator they'll find this clue near the asparagus. This one forces them to do some encryption. Once they figure out that it spells bed they will run there and discover their prize!
I generally make my clue sheets by ripping a few sheets of computer paper into 4 sections. When I make the clues I keep my kids ages in mind. If my oldest son is the one doing the treasure hunting I make the clues a little more difficult. If my youngest son is playing I make everything a picture that he will recognize because he can't read yet.
Be creative and imaginative! There are so many different ways you can keep your kids occupied with this game. Hopefully they have as much fun as my kids finding their treasure!