After last month's single life challenge (which I was predictably terrible at), today / tomorrow (2nd March) people are encouraged to go watch people on twitch.tv torturing themselves with a no Estus flask challenge, or to take part themselves. Last month £500 was raised for Refuge, a UK charity who support women suffering from domestic abuse, and this time it is Co-ordinated Action Against Domestic Abuse who money is being raised for.
If you're looking at Dark Souls streams on twitch.tv this weekend you should see some with [WKC] in the title, check them out.
The site is http://whiteknightchallenge.org/
I think there are quite a few good players signed up this time so it should be fun viewing.