People can create a thread in the general section, and if it shows potential, mods would most likely move it to the activities section.
Personally I am just concerned there could be a flood of these, so I'd like people to only do it if there seems to be a lack of activities.
Right now we have the commercial critique as well as the smiley face activities which are fairly new in the activities section which could use some participation.
If there is support for the "Show and Tell" idea, we could pick a day for that and set that up, otherwise we could keep discussing the subject of consistent weekly challenges and see what other ideas there are..