I think the question should be "what services can I rendered to make 0.1btc par week" to earned 0.1btc is easy if you have any digital skills such as video or audio editing, forex trading, photoshop and website design. You may have the skills but you also need dedication and commitment to work things out.
Knowing just a few people has such skills, and competition makes the price going down isnt soo easy as looks like to make such income weekly. Normal people without web skills to create anything are the most present over online earnings, the most of them does earn a big ammount from signatures, outside those only trading is a reliable source, while gambling is a very risk attempt to get more coins.
Gambling can give you that amount occasionally depending on your luck but apart from that I think trading is a place from where you can generate that profits frequently if you know what is the market scenario but there is also a risk of loosing money in trading but comparatively its better then gambling for sure.