I think there is no secret about 0.1 BTC method to get within one week, because it includes an easy thing, you can combine a variety of methods such as trade, signature campaign, services, faucets, PTC, etc.
even you can earn more than 0.1 BTC
yeah if you combine different methods of earning it then you can surely earn about that level in a week, and I don't think it would be hard to earn that amount as 0.1 btc is not too huge.