What are some great OS X Dropbox uses? There are a number of ways I use my Dropbox with OS X apps, or iOS devices.

Some of them include:


Recipe tracking: I keep a 'recipes' folder inside Together's dropbox-synced-library, so from my Mac I can drag recipe web pages to the folder keeping them as PDF's, and view them on my iPad while I cook. It also works with text-recipes I've created inside Together.
iCal sync: I have The Hit List synced with iCal and keep its library to Dropbox, so iCal's library is being synced to all computers, along with all other apps relying on it (Alarms app)
PDF to iBooks: The easiest way to send a PDF to your iBooks..


I can't wait to read about yours clever/unique/nifty ways you're using Dropbox on your Mac / iOS devices.

Rules


One answer per post
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Please keep the answers relative to OSX/iOS. No general Dropbox uses!
It would be nice if you provide a bold title to your answer. That way it would be easier to parse/search them.
1Password sync

Syncing 1Password's stored keychain across my Macs. I use 1Password for managing passwords and, more importantly, auto-generating random passwords so that I never use the same password twice. Dropbox makes this much easier. 

1Password's secure keychain file lives on my Dropbox, and each time a password is added or updated it's automatically sync'd across all my computers.