Think about things that can be de-centralized like a decentralized casino? decentralized Steam? i dont know. Think by yourself but repeat, don't do an ICO
Decentralized services might work, to certain degree. Decentralization is not some magic keyword which will automatically make everything better.
vDice is decentralized gambling platform, but their decentralization is just based on using various other services to verify their authenticity.
For example - random.org - is used to generate perfect random outcome of the bet. But what will happen in a case when random.org would turn out to be badly coded?