There's honestly a lot more I could talk about, but for now here's a good list of places you should consider checking out on campus while you're here.
On Campus:
First of all, gameday stuff. I would definitely recommend going through the tailgating lots if that's your thing. Best lots to go through, in my opinion, are the Blue lot, Silver lot and Black lot. I've also gone to the Green lot before, where everyone is very nice, might be a good one to hit if you walk around campus a bit. There are also some events going on at Kaufman Mall, and that's probably where USM will have an Alumni booth if they decide to bring one.
If you want to walk around campus a little bit the areas I'd suggest you hit would be:
Kaufman Mall: Take a picture with the lion fountain!. If your son is thinking of attending the university, make sure he DOESN'T step on the University Seal at the crossroads of the walkways in the middle of Kaufman Mall. If he does, he'll never graduate ODU (you can step on it once you graduate).
Perry Library: I know the Library may not be the coolest place for a highschooler to go, but I spent a TON of time here when I went to ODU. It's a really good resource that has tons of fantastic nooks and crannies to study in. I would not have graduated had it not been for #ClubPerry. The first floor was recently renovated to include group study spaces, a café, a computer lounge and general study space.
The Quad: I lived here for one year. Very nice dorms that are close walking distance to basically everything on Campus. It was usually a 5-7 minute walk to all of my classes when I lived there.
Monarch Rec Center: On the other side of that grass field as the Quad. Played a lot of pickup basketball here. Has a lot of exercise machines, yoga/flex rooms, racquetball courts, rock-climing wall, basketball/volleyball courts, indoor soccer court and soccer/grass field in the back. If you want a tour just walk up to the front desk and someone should be able to help you.
Broderick Dining Hall: It is literally brand new. So new I can't find good pictures of it online. I'm not certain if students can eat in there yet, but it should definitely be open by the time you head down. Don't know how good the food is going to be yet though.
Whitehurst Beach: I wouldn't put this at the top of my list. It's nice to have a beach on campus, but it's a bit out of the way from the center of campus, and is very very tiny. But! There is a great dock there and students can rent kayaks and whatnot from the Rec Center to go down the river.
The Monorail!!! If you are headed to Old Dominion, you were going to see it eventually. It was constructed as part of a Federal grant to research Maglev technologies. There were issues and since then the project has been scaled back to only the section of track by the Rec Center. Right now the University is trying to figure out what they want to do with it. To students, it is known as "The Most Expensive Umbrella Ever Made!"
University Village: I lived here for a few years. Very nice upperclassman university apartments. A lot of good restaurants are on Monarch Way like La Huradura, Raising Canes, and Mojo Bones. Right behind the Ted Constant Convocation Center.
Art Square: Not sure if this is the official name of the area or not, but at the end of Monarch Way is a bunch of brand new art buildings that have popped up as ODU continues to try and lift up its burgeoning art program.