A few themes came up across the projects as well.
Glen, Toby, Bret, Paula all needed to be able to track the arrangement of tokens/foamcores/coasters on a table/placemat/whiteboard. Bret suggested making a generic PCB-in-a-foamcore that can be tracked on a "smart table", and then producing ~1000 of these. This way we don't each have to reinvent this tracking capability.
"Active pictures" came up as well. For example, Toby wants to be able to "collapse" a set of video processing nodes into a single node. Glen suggested being able to take the whiteboard scale representation and squash it into a picture on a piece of paper. But in the squashed version, you still want this smaller representation to be dynamic. Likewise, Paula's calendar wants to be able to print pages out that still have the dynamic behavior (e.g. get more details of an event) of the original whiteboard calendar.
Many of the projects seem to suggest a feature of "dynamic binding". For example, we brought up different ways of creating sliders and knobs, for example the distance between two tokens, the placement of a token on a drawn line, or the distance between your hands (Paula's air-tape-measure). You would want to be able to hook these up to other objects in the system, for example to use the slider to scrub through a video. Also, for "mashups", e.g. taking one of Glen's video coasters and hooking the sound up to Bret's DSP graph, one would want to be able to take an arbitrary output and plug it in to an arbitrary input. (This dynamic binding is exactly my vision of "physical apparatus".)
Are there any other themes that came up?