Each week, your team should update your team’s wiki page. If you do a great job documenting everything, it will make your final report much, MUCH easier to write.
The wiki should include key documents (project specs, etc.), an ever-changing schedule, photos from experiments, scans of best brainstormed ideas, etc. It should also contain a weekly report on your communications with your community partner (you should do everything in your power — regular emails and/or phone calls to stay in touch) so that they are up to date on your progress and can offer feedback.