Starting a running list here of things to make sure get explained.
When creating a future series, you must set the Entry Date to at least the day after the previous series ends, so that it doesn't show up until it's time. On the date set as the Entry Date, that series will become the "Current Series", featured in the biggest block on the homepage. Note that if at least the basic series information (minimum required fields: Title and Description) is not entered by that date, it will look strange.
When creating an event, you must set the Entry Date to the same date as the Event Start Date for proper detection of which events are in the future. (Things can still get hairy with multiple/overlappingn events. May need to think harder about how to handle this on the homepage.)
Starting a running list here of things to make sure get explained.