No I’m not talking about something to take notes on during the sessions (you’ll want that as well, either paper or digital). But you’ll want to bring some business cards. Even if you aren’t a consultant, business cards are a great way to give someone your contact info so that you can get in touch later to talk about what ever it is that needs following up on.
You may have a technical question that you want to give someone more info about, or a business idea, or maybe you ran into someone who works in the same area of the world as you and you want to get together for lunch and chat somewhere slightly less crazy than the summit. Being able to hand out cards is a much better idea than having everyone write your info down on their hand like back in high school. One spilled drink and all that contact info would be lost.
Now personally I’ve gone a step further and made it even easier to get my contact info from my card into your phone or computer. When you look at the back of my cards you’ll see a Microsoft Tag that will automatically put my contact info into your phone when you use the Microsoft Tag viewer to take a picture 
of it. These tags are great, and free because personally I hate entering a few dozen new contacts into Outlook (I’ve got an app on my phone call CamCard that will do most of the work these days). And the logo that the Microsoft Tag uses is all colorful adding a little extra splash of color. If you don’t want to use a Microsoft tag, you can also use a QR Code to do the same kind of thing.
Now it’s probably to late to order cards in time for the PASS summit without paying a fortune for shipping, but if you don’t have any you can hit up Office Max or the Fed Ex stores (the ones that used to be Kinko’s) as they both have same day printing options that look OK (the paper stock they use isn’t the best) and won’t kill you on price. If you are really desperate you can grab the print at home kits. I’ve tried these and wasn’t all that thrilled with the results, but I was printing on a ink-jet printer. If you have access to a nice color laser printer at the office you might be better results.
If you run into someone that you’d like to get in touch with later, give them your card and get one back from them. We pay for these things for a reason, lets use them to make some new friends.
Denny