totally agree! I have suggestion:
the leader could give out some pratice and challenge question.
for pratice is aim for ID beginner and anybody who would like to improve their sketch, or design skill...do the excerside got the point. encourage people to come in.
the more challenge question , could be a design assignment, to solve the design problem and compete with best design solution. aim for anyone like to challenge.... good solution, good design got the point . also encourage or at least make the atmosphere heat up....