A quick and dirty utility to note what you're doing at a given time. Pops up every 15 minutes on its own, or double-click the tray icon to write down what you're doing and it'll leave you alone for 15 minutes.
When timesheet time comes around, right-click the icon and choose "History" to see what you wrote.
When you exit, your recorded history is persisted to AppData/Roaming/TimeTracker/records.txt