Yes, there are atheist working together for charity. A person shouldn't need to do it in the name of something though. For the record if a theist is giving up on arguments to prove their god and is trying to just get you to leave it alone you have them backed into a cornor.

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The 'good effect' of religion interests me.
It's clear that religion mostly gives people a warped vision of ethics but it can also motivate people to be more ethical so there's a bit of a dilemna.

That's why people find forms of Buddhism and Pantheism very attractive as they contain the common-sense-based humanistic ethics alongside a mystic philosophy that motivates 'spiritual' practice.

Yes, there are plent of religious people who do good, but the question you should ask yourself is that do these people do so because they are religious or because they are good people to begin with? There are lots of awful religious people who commit terrible atrocities because they are religious. As Bertrand Russell said, good people will do good things and bad people will do bad things. But for good people to do bad things, that takes religion.

Studying neurology, I often ponder what drives a supposedly rational being, a human, to create religion. I suggested that it is a by-product of our morality (not vice-versa), and that it was called upon to fill in the gaps where science did not understand, to appease the questioning nature of man.

The irony of course is that people still subscribe to it in this age where most of it has been debunked. 

Religion does do many good things, but the counterweight created by the evil it produces means that it is probably not, as a sum total, a force for good. 

Any good that can come from religion can just as easily come from any secular organization. Unless your idea of goodness is being complacent with ignorance...