Syncing from iPhone

If you're running OS X 10.7.4 or higher and have enabled iCloud syncing as explained here: http://www.apple.com/icloud/setup/mac.html, your data should be synced to your Mac. If it doesn't, start by going to icloud.com, sign into your iCloud accout and confirm that your contacts and calendar appear. If they don't, then your phone is not properly syncing your data to your iCloud account.

Are you syncing your contacts and calendars with iCloud, iTunes or both?

Connect your phone and go to the Info tab of your iTunes sync settings and make sure you haven't checked either Sync Calendars or Sync Contacts. If you have, uncheck them and sync. See if the duplicates still remain on your phone.

Not yet, just click Cancel. Then check Settings>iCloud on your phone and make sure Calendars (and Contacts) are set to On. Then open your calendar on your phone, tap Calendars at the top, and tell me which one(s) are listed under your iCloud account name, and which other one(s) are listed here.

Ok, you mentioned earlier that you were having an issue with the Home and Calendar calendars. I suspect that the issue traces to the fact that you have multiple calendars with this same name. Only the "Home", "Calendar" and "Work" calendars listed under the iCloud heading will sync with your iCloud account. And if you try to sync with both iTuens and iCloud you will end up with duplicates. What you should do at this point is on this same screen on your phone, check only the calendars listed under "iCloud" and "Subscribed", then tap Done and check your calendar. This is how it will appear if you uncheck Sync Calendars in iTunes, sync and let iTunes delete the calendars it is syncing.

If you are satisfied with this, do the following:

1. On you Mac, open iCal (Calendar), go to File>Export>Calendar Archive, and save this file on your desktop. This will be your backup in case something goes wrong.
2. Next, reconnect your phone to iTunes, uncheck Sync Calendars (and Sync Contacts if that is also checked), click Apply and sync, allowing it to remove synced calendars.
3. Eject your phone and check your calendar and check your calendar to be sure everything is still intact.
4. Go to Settings>Mail,Contact>Calendars...scroll down to the Calendars section and tap Default Calendar and make sure the calendar you want to be your default when you enter new events on your phone is selected.

I should also mention that I am assuming that you are syning your Mac with your iCloud account. Let me know if that is not the case. Also, be sure that the default calendar you select on your phone is one of the ones listed under your iCloud account name, and not one of the ones listed under On My iPhone.

Under iCloud. You shouldn't need to re-sync unless you haven't done so at step 2. Also, let me know if you are syncing your mac with your iCloud account.

That's probably because they were entered on one of the calendars listed under On My iPhone, which doesn't sync with iCloud. You can check by opening the calendar on your phone, tap Calendars, then check only the calendars listed under On My iPhone and tap Done. If the missing events appear now, the only way to sync them to your Mac via iCloud is to manually enter these on one of the calendars listed under iCloud. After doing so, go back and check only the calendars listed under iCloud so you won't see any duplicate entries on your phone (because you will no longer be viewing the ones on the On My iPhone calendars).