I've been using Minuteur since it was still a freeware app, and I've loved it ever since. I must use it several times every day, for tracking tasks, for making sure to get ready on time, etc. This is definitely one of my "must haves".
If you're getting the OutOfBoundsException error, try deleting ~/Library/Preferences/Minuteur and running the program again.
Minuteur
Timer and stopwatch app.
Version: 5.3.3