About grade 10 I built myself an excel spreadsheet to keep track of all my school classes, naturally. It started off simple enough, with a list of classes with start times, end times, categories, etc.
However, I then decided I wanted a schedule for each week, with the five school days at the top and my time broken into 15 minute chunks down the left side. So, I began with a simple cell formula which would figure out what day and time slot it was for and figure out what class was happening at that time. I also created an indicator on my schedule that would highlight the day of week and time block I was currently on. This was all fairly easily.
I then created sophisticated formatting rules so that if a class name was repeated it would be hidden, so that it would only show once for each class, not in every 15 minute block. I refined this further so that every class had a border around it. Then, I created one formatting rule for each category of class, so that each category could have it's own color.
Finally, I added a checkbox to the class list so that I could check off classes as I completed them. This, of course required more conditional formatting on the schedule to hide classes that were completed.
It took me a few months to finish my schedule, but I was very happy with it, and while I was working on it I probably learned as many life skills from the project as I did from school.