Do something that could be used by the staff in ur college/school. Mostly mark entry, attendance record, progress report generation, mark allotment for tests and practical classes are the most repetitive and demanding tasks that teachers do manually. (There are many more tasks that might improve efficiency of staffs in, for example, library or labs. Just inquire them in the analysis phase of ur project.) U can try to computerize it if they haven't a system already in place, that is. U can pass on support and maintenance tasks to your junniors afer u are gone.