Circle writing :
can be done on papers or IT devices. A student writes a line or two, and then moves on to the next paper/device, continuing the story there etc
Give an intriguing sentence. Students start composing a story or a newspaper article about it.
Convincing a sponsor:
Write an e-mail to convince your sponsor to give you certain money for certain things...
Consider: salutation, background and the description of the situation, arguments for and against the decision, conclusions, request, sign-off.