Я экстенсивно использовал Bugzilla (значение по умолчанию для проектов на работе), но Богомол получает мой голос за легкую установку и использование.
If your question is: "How do I execute a delegate every full second/minute/hour?"
For minute and hour intervals, you could do something like shown in my answer in this SO question:
This should be fairly accurate, but won't be exact to the millisecond.
For second intervals, I'd go with a Timer with a simple 1-second-interval. From a user's perspective I think there's not a lot of difference if the action executes at xx:xx:xx.000 or at xx:xx:xx.350.
You can subscribe to SystemEvents.TimeChanged. This fires when the system clock is altered.