A great resource to inspire writing is Pobble 365. You get a new picture everyday and there are brilliant writing ideas to go along with the picture. Ask questions about the picture as we do in school- our Tell Me grid- What do you like? What do you dislike? Is there anything puzzling or strange about this? What might happen? Does it remind you of anything?Then use the story starter section to complete the story or "fix" the sad sentences.
You could write a story about something that happens when you're off school or write a diary.
In addition to this resource, I've attached some writing based activities.