Windows: Dropbox is an amazing utility, but one of the occasionally frustrating limitations is that you can only sync folders within Dropbox itself. Boxifier allows you to sync folders outside of your primary Dropbox structure.
Boxifier allows you to designate specific folders anywhere on your drive, and those will be synced or backed up to Dropbox. This may be particularly handy if, say, you want to backup game saves that have to be stored in a single folder within a game's existing file structure.
Boxifier | via One Thing Well