I am thinking about this for Lisk: Stream live videos and get paid with ⱠISK instantly. You choose how much ⱠISK per minute it costs to watch the stream and people pay e.g. for 10 minutes. If they close the stream after 5 minutes, they get refunds automatically. Well, streaming is not possible with a DApp but maybe you can build a DApp which works for the transaction-stuff.
The project is great! It seems this market will be growing rapidly for years. I think the crucial factor determining success of Lisk will be how easily end-users can purchase Lisk when they find interesting product. Ideally would be to have a quick credit card/Lisk exchange built-into the dapps and Lisk client