I have given up using the evaluation technique in which you ask people, "If this meeting were a pair of shoes, what kind of shoes would they be? Roman Sandals? Pumps? Flippers?" Or, "If this workshop was a cup of coffee what kind of coffee would it be? Espresso? Turkish coffee? Soy or whole milk?" (I like that kind of thing, but I have found that not everyone does!)
But, we can borrow a tool used to evaluate coffee and other things to evaluate our work: the radar chart. (http://en.wikipedia.org/wiki/Radar_chart)
The idea is to choose a set of evaluation criteria (fewer than six is probably best, if you want the resulting chart to readable at a glance) and make a big chart on paper or a whyteboard with each criterion a point in a geometric figure, like the points on a triangle or hexagon. Place a dot in the center, draw faint lines going out to each point and perimeter lines. The center represents zero and each outer point represents 100%.
Participants then put a mark/place a sticker somewhere along each axis to show their evaluation on a scale of 0 to 100%, drawing lines to connect the dots when they are done. (It is best to have fewer than eight people per chart and use different colors so the chart is easy to read when finished.)
The resulting chart shows both how the group as a whole is feeling/their evaluation and how the feelings/evaluations differ within the group. It is important for everyone in the room to be in the chart, including teachers, jokers, facilitators, what have you. (If you can see my evaluation, I should be able to see yours.)
For an example of one use I have made of the radar chart see Feel Free in which COMFORTABLE, UNCOMFORTABLE, and LOVED are the three axes. Each participant marks his/her degree of comfort, discomfort and belovedness on the chart connecting the dots to form a triangle.
The debrief can be the usual: what do you see? what questions do you have? what do you think about this? what should we do about it? But, in some cases it is enough to just do the activity as a check-in, with no need to debrief. It may be enough that we all know how we are feeling.