To-do syncing has always been one of the gaping holes on the productivity side of the iPhone and iPod touch. Several third-party apps have filled this hole, but with Google Sync, to-do syncing gets even better.
Stacks is an add-on for jailbroken, or hacked, iPhones which brings a distinctly Mac-like tweak to the iPhone UI. As the video shows, Stacks lets you replace the icons in the home row (the non-moving row of icons at the bottom of the screen) with, well, stacks.