I did not know that you're not able to create a multi-day reoccurring event in SharePoint.
There are a lot of discussions about that.
Basically, as soon as you check "Make this a repeating event", the date field for Start/End Time disappears:
That's valid for both SharePoint 2007 and 2010.
Hmm... how would create an event to show that I have Friday-Sunday off every week for example? Well, it may be not a real case, but the real one is migrating Outlook Calendars to SharePoint.