Swag is often a commodity that is very forgettable. Google stepped it up this year ( in addition to some high tech goodies ) by adding a low fi leave behind this year. A slim packet unfolds into a cardboard virtual reality headset. An NFC chip preloads an app and you can look around a variety of google earth views. I got to try this out myself and I was rather impressed.
Takeaway: If you want to leave an impression – do something different. Often a combination of digital and analog can be most memorable, but you need to have a very low barrier to entry. Kudos for google for breaking ground with something so simple but buzzworthy.