Back when I was a student and worked at STEM I was filling out my timesheet and thought to myself "man, the computer should be checking my timesheet for mistakes. It'd save me so much time!" So, I took a couple days of my spring break and I made the computer do just that.
The idea is pretty simple: have VBA macros in Excel enforce correctness and try to find potential mistakes. Times worked were recorded to the nearest 15 minutes, we could only work a maximum of 30 hours/week as part time students, we needed to record basic information on our activities as tutors, and the times needed to be formatted correctly.
The code works using the magic of Regular Expressions. It saved employees a lot of time on filling out timesheets and gave the student assistants fewer headaches dealing with "bounced" time sheets. The code isn't the prettiest, but it works quite well! In fact, I believe they use the timesheet to this very day.
The macros work in both Microsoft Office 2010 and Microsoft Office 2013.