Here is a video of how BITWIN24 does their bitcoin lottery - https://youtu.be/6r1SvPbVrTE

Here is a gamble that might be interesting - They run a bitcoin lottery based on picking a series of numbers in BTC block hashes.
 
They have a jackpot up to €1,400,000 - Paid in Bitcoin

Check them out, I would love to hear some feedback and happy to discuss.