Sometimes the formality of meetups is too much. This group exists to socialize and show off your latest piece of hardware. If it's a simple Arduino based thingamabob or your company's newest hardware product (and how you earn your living), you should consider attending. The main focus is meeting like minded people who are building fun things (with atoms!)
This group is based upon the idea that you are interested in hanging out and discussing hardware. Please bring a piece of hardware to show off or talk about. Are you interested in hardware, but you haven't built anything yet? Show off software you have built! Or come prepared to talk about the projects you want to build.
There are no organized talks, it's literally a show and tell at a bar or restaurant. In case you missed it two paragraphs ago, bring hardware. Seriously, just bring anything to talk about :-)