Where can I find an idea for visualization/working with data?

Question

infographics

Hello.
I know that now there are wonderful open data portals data.mos.ru and data.gov.ru
But the question is the following. I found a site about a year ago where there were some kind of "challenges" for visualization. As I remember, there, for example, it was proposed to work with the data of the registry offices of Moscow. and something else. Can anyone remember what kind of resource? Are there any analogues (forum, community where visualization topics are offered)?
Can anyone recommend something other than that?
Thank you.
UPD:
I found the same site with "calls" - infographer.ru/open-projects
The question is still relevant for similar resources. Can be foreign.