We investigate engaging a computer science conference audience in sketching responses to the event as it occurs. In particular, we explore the response to inviting those present to engage in what is essentially an off-line, co-located, attendee-sourcing experience. Sketchnoting is a popular practice for documenting events, but these sketched records can be limited in scope at multi-track conferences, and paid professionals can be unaffordable at smaller events. Our challenges included: working with an audience with little or no experience of sketching or working with imagery; who were unaware of the possible benefits; and whose attendee engagement was variable - with individuals often working on laptops rather than actively listening during sessions. In order encourage engagement we hosted a pre-conference workshop, developed a conference-specific set of visual icons, and created prompt materials. This resulted in a remarkable visual record of the event, and also an increase in active listening and engagement.