abandoned - ARC has quite a few abandoned buildings.  The McDonalds is closed, for instance.  Seriously, stop knocking on the drive-thru window asking for a cup of coffee an Egg McMuffin, you're embarrassing yourself.

bicycles - ARC is bike friendly, but helmets are required.  You will be stopped without one, and you can be ticketed.

cell phones - The use of cell phones while driving is prohibited by Federal law on ARC and by state law in the rest of California.  So don't do it.

earthquakes - You'll be briefed on what to do when you get here, so pay attention.

gates - The main gate is staffed 24/7, most others are locked evenings and weekends.

intern listservs - Here are two handy email lists, from which you can learn all sorts of things both business and social.

Internet and Email 

Organization Codes - Get your Organization Codes here! Can't tell the Astrophysics Branch (SSA) from the Exobiology Branch (SSX) without Organization Codes!  Ahem, sorry.  Also referred to simply as "Codes", these are unique identifiers for different groups within NASA ARC. Useful for all sorts of official business, and for knowing what on Earth some of your colleagues here are talking about when they start spouting abbreviations.  You could also use them to deliberately confuse new arrivals, but that would be cruel.

police - They're not just security, they're actual police.  Since ARC doesn't have much in the way of serious crime, they're frequently bored.  Which means you should follow traffic laws and stuff, because you really will be stopped if you don't.

roadside assistance - Getting a tow or a jump start inside the fence may not be easy, but it can be done. 

weather - Sunny during the day, chillier than you may expect at night, not much in the way of rain.  Keep sunscreen handy, and bring a jacket if you're going to be out after dark.  And call your mother, she worries.