If you accidently deleted items like Emails, contacts, calendar, tasks, etc from your mailbox using Outlook, you can recover them as they are first transferred to the Deleted Items folder of that mailbox. But even if you delete them from the Deleted Items folder you can still recover them. This feature is enabled by default in Outlook 2007 but if you are using 2003 then you’ll have to modify your system registry.
Enabling recovery of deleted items in Outlook 2003:
1. Start Registry Editor (Regedt32.exe).
2. Locate and click the following key in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\Client\Options
3. On the Edit menu, click Add Value, and then add the following registry value:
Value name: DumpsterAlwaysOn
Data type: DWORD
Value data: 1
4. Close the Registry Editor.
Now when you start Microsoft Outlook 2003 you’ll be able to see a new option- Recover Deleted Items in the tools menu.

Recovering deleted items in Outlook 2007:
1. In the folder from where you deleted the item, or in the Deleted Items folder, click 2. Recover Deleted Items on the Tools menu.
Click an item and then click Recover Selected Items
NOTE: If an item doesn’t appear in the Recover Deleted Items dialog box then you can’t recover it.
I did the did regedit but it did not work. ( I’m using the junk OS Vista) But I found a work around. Drag the deleted Calendar item over to the calendar and it restored the series.
I just wrote a detailed step-by-step on the very subject as well as explaining a few other items. Hope this helps a few of the readers: http://www.groovypost.com/howto/microsoft/outlook/recover-deleted-email-in-microsoft-outlook-from-any-folder/
A bit confused what you did here. Did you drag the Calendar item OUT of the deleted items folder or the dumpster bin? or?
This only works if you are using Outlook with an Exchange Server. This will not work for POP3 accounts etc.
I have accidentally removed all my contacts from Outlook while synching with HTC Mogul. Help!I have Outlook2007 but I do not see “Recover Deleted Items” under Tools.