How Create a Scheduler (e.g. to schedule tweets, or an api request)

Question

I have a table of schedule items, they may be scheduled for the same time. I\'m wondering how to have them all execute at the correct time when:

The problem I see is

Answer 1

I would use a Windows service to accomplish this. Then each of the items should be scheduled asynchronously using the BackgroundWorker process. This would allow all of the scheduled processes to be launched rapidly asynchronously so they don't collide and aren't depending on the previous one finishing before kicking off.