Specify the size and grid style of the maze in the "control panel" on the left. When "Create maze" is clicked, a maze is created using the "DFS" algorithm (described and illustrated here), and all the dead ends in the maze are marked. One of those dead ends was the starting point for the maze creation process—can you determine which one? Click on a cell to see.
Once you know the secret, you can a-maze your friends: While you look away, have them click on "Reset maze," then click on any cell in the grid to create a maze starting from that cell. Then you can tell them which cell they started on ...
If your friends know the secret, you can challenge them to a race to find the starting point.
(update 10/14/2013) After you find the right answer, you can click on any dead end to see a "hint" that might help you to understand the secret.
(update 1/21/2015) Added the option (enabled by default) to not show any "easy" puzzles. Also made some tweaks to the maze-generation infrastructure.
Short link to this page: tinyurl.com/mazepuzzle
Copyright information:
Both the "red x" 
and
"thumbs up"
icons come from Wikimedia Commons, where they were released (respectively)
under the GNU Free Documentation License and into the public domain.
The other images are mine, as is most of the JavaScript code for this page. (More information about JS sources can be found in the .js files.)