'Pseudo Groups' created so far ...

Please post a link in the comments to allow maintaing a kind of a group list - and if possible a short description of its purpose. For Contest's and Duel's, Don Gato (Toni) already maintains a great list here.
Let me start with those I know ...

Macro Photography

by Nastasha

Lets start a new group specially for macro photography. Show us your closest shots!
The rules: You must have 500 votes and 5 invititations min to... no, a joke. ;-)
The only rule: The pictures must be closeups. Everybody can join! :)

Doomed for Eternity

by Lutz

Seeing more and more fantastiv images making their way into the new community, and waiting for groups to be implemented, I've wanted to create a space for these masterpieces which are a milestone in technical and/or creative Quality - in other words 'Doomed for Eternity' (love the little analogy to our new platform ;))

Best of the Week

by Roberto

'Best of the Week' is both a group and a contest. Every week we'll post the shot we prefer fromour streams and we'll vote for the preceding one. A blog/group will host the most appreciated shots of each week.

Minimalism

by Manganite

Maybe I should also start a pseudo group. There's nothing for minimalistic shots, so post them here!

Black & White

by Manganite

I think you all have some beautiful black and white captures in your streams, so poste them here. And if you came along a wonderful b&w capture in your friends stream, invite him to this group.