I recently did a flyout to visit ESPN to interview for a role as a mobile software engineer, so I'll offer a few points about my experience there that might help folks in a general sense, as well as some points for those interviewing for software engineer roles in a specific sense.
The first thing was that the interviewing process took at least a month or maybe closer to two months. This may have been because of the holidays (before & after Thanksgiving & Christmas) or it might have been because this ESPN group wasn't super urgent on making decisions. I did manage to pass all the various phone screens and phone conversations (the technical questions and "getting to know you" calls with the higher ups). It was at that point the H.R. drone arranged for me to do the trip.
ESPN appears to be somewhat strict with how they do fly-outs: travel to & from your home airport is not reimbursed (i.e. if you have to take a taxi, you must pay for that out of pocket). They also will not cover GPS charges for the rental car, but printed-out Google map directions almost worked perfectly (see note in next paragraph). They only pay for two meals & one night's hotel, so if you want to see a bit of the area, you'll have to pay for the second night yourself. The hotel they put me up at, the Clarion, was under severe renovation and was not a good night's sleep… but after March of 2013, the hotel will be re-flagged as a DoubleTree by Hilton and should be somewhat more comfortable.
Regarding the campus, it's an impressive collection of buildings surrounded by an iron fence. Now here is where you need to be a bit careful in your driving: if you follow Google's directions (or even the BING instructions that your H.R. resource sends you), it will send you to a closed gate (which used to be a public street named "Birch"). You'll find an open gate between the former "Birch" street and Middle Street but it's also the wrong entrance. Instead of that "North" gate, you actually want to go in the "South" gate… which you can reach by going a little further south on Middle Street and then turning left on West street. And this is where you'll find Building 9, which is the security building where all candidates check in.
Speaking of security, I've never seen tighter or more visible security in any other corporate installation. You must show your ID to get past the South gate, then again when you end up in Building 9 to get your "visitor" sticker. Lastly, you'll park your car and get driven in a security van to where your interview will be and your first interviewer will be waiting for you in the lobby. If you'd like to use the Internet while on campus (e.g. if you want to demonstrate something you've done that requires remote server access, or show off apps that live on a non-ESPN website), you must ask the hiring manager to issue you a temporary password which will get you onto the guest WiFi network.
One thing that irritated me significantly was the H.R. person insisted that I wear a business suit to the engineering interview. I tend to "dress nicely" for West Coast interviews (because suits are far too formal for waving my arms while doing technical explanations in front of a well worn white board) and I also "dress better" for East Coast interviews. For ESPN, I ended up buying an expensive brand new suit. When I showed up on-site, nobody was dressed more formal than cargo or khaki pants, t-shirts and sweatshirts (multiple layers for variable indoor & outdoor weather, etc.) and I ended up being quite uncomfortable -- and feeling quite overdressed -- while trying to explain myself & my background. It's still probably a safe bet to wear a suit if your interview is **NOT** for an engineering role.
I probably shouldn't have to remind you, but even if you're interviewing for an engineering role, try to get as familiar as you can with the products you might end up working with. Another important thing is to try to drop as many sports-related anecdotes as possible. If you can admit to being a sports nut and it sounds credible, that's likely to be a big plus.
Another thing that made me uncomfortable was the age difference between me (I'm early 40's) and the engineering team, the oldest of them might have been 34 or 35. Some of the guys I spoke with have only been with ESPN since getting out of school years ago, which is almost unheard of in the computer science world (which usually has more frequent job jumping); but then again, the benefits at ESPN are indeed quite impressive (ESPN is the only company I've heard of that actually continues to offer pensions).
In any event, I was glad to get to visit ESPN and I hope my experience flunking the interview will help you to prepare and pass yours. If my interview notes helped you out, please let me know by voting "yes" on the "Helpful?" question below.