There are a ton of stories out there, but for one that I remember from a basic squadmate...this is one of the unintentional ones. He was wearing University of Illinois basketball shorts when he in-processed. Well, he ended up being spotted by the captain of the basketball team, who pretty much took him under ownership for the rest of the day and gave him heck about his shorts. There's also our dear redhead, who happened to in-process with a HUGE pink suitcase.
Then there's always the guys with ridiculously long hair, or the t-shirts that stick out such as the sports shirts or Superman logos.
Now you'll notice these things are small and unoffensive, but enough to be of some interest to the cadre and be at least a little of a story later...something that will make people laugh and ask questions about your experience. When it's my turn to talk about I-day, I don't have anything to share for it. That was essentially my point...keep in mind that you want to be able to look back and laugh...which is also a reason to shrug off the stupid things you'll do or say during basic. They're just that much more fun to reminisce about.