Two months ago, I started a proposal on StackExchange on Mathematical Challenges for "enthusiasts wanting to create and share their own mathematical challenges at all levels, including recreational mathematics."
The link is here: http://area51.stackexchange.com/proposals/119894/math-challenges
The example questions are questions that would be typical on the site. Please note that for the purposes of an example question, it doesn't have to be original, but all questions posted when the site is in beta (see below) must be original.
Currently, it is in the Definition phase. If there are 60 followers and 40 questions with a score of at least 10, then it will move on to the Commitment phase. After this it will go to beta (where users can actually use the site!)
As of now, it has 80 followers and only 14 questions with a score of at least 10.
>>> If you are interested, I'd be really grateful if you could upvote 5 example questions that haven't reached a score of 10 yet, and if you can, propose more example questions!
To propose a question, you need at least 50 reputation, so the best way to get this is to
follow the proposal (click Follow) by entering your email - it will not be displayed to anyone else
you will be directed to a new page and press "Confirm and Create Account"
click on your profile picture on the top bar of the page
click on 'Send email verification' and verify your email to get 50 rep
finally, go back to the link above and scroll to the bottom. You will see a box where you can enter your example questions!
If you have any further questions, feel free to ask them here, or discuss on the Area 51 Meta site: https://area51.meta.stackexchange.com