Vdice.io is one ethereum based gambling platform which have collected good amount of ethereum during ICO here in this forum.

You can check below links which may help you to understand how they have conducted their ICO successfully.
https://www.vdice.io/
https://bitcointalk.org/index.php?topic=1658298.0 [ANN] vDice Ethereum Blockchain Gambling || Crowdsale
https://bitcointalk.org/index.php?topic=1633105.0 [ANN]★vDice Ethereum Blockchain Gambling★ || [ProfitContainer is Deployed]
https://bitcointalk.org/index.php?topic=1691524.0 [ANN] [vSLICE] ★A Profit Sharing Token for vDice★ [ProfitContainer is Deployed]