RoboJo Timesheet Tracker
Every job I've had has required me to do timesheets either at the end of the week or the month, or in one case I was expected to do them once per year. Naturally it can be challenging to remember exactly what you were working on and for how long, especially if you are juggling multiple projects or clients. Over time I started to do a better job of keeping notes but often there were days that I wrote almost nothing down. Eventually I decided I wanted to create a simple C# desktop application to nag me every 30 minutes to make a quick note of what I was doing and then at the end of the day I would have a good breakdown of what I had worked on.
I've been using it daily for a year now and it has greatly improved the accuracy of my timesheets and has drastically reduced the amount of time and effort it takes to enter them into my company's propritary software at the end of the week. I've also found it has the added benefit of increasing my productivity because the constant reminder to log what you're working on makes you more aware of where you're wasting time or even when your less productive times of day are.