Welcome to the boards, and prematurely welcome to Lincoln!
Football comments aside, my quick rundown of Lincoln tailgating is as follows:
1) Embassy (The Embassy Suites) has a bit of a monopoly on big, expensive, dt tailgating. They have the room, resources and staff to back it up. It's always worth stopping by, the inside of the hotel has a huge atrium all the way up, 15(?) stories from the large ground floor where all the bars and restaurants are. As mentioned, they also have a big space out back on their loading docks (Easily visible, flying flags from all B12 schools). Biggest downfall is simply that they are pricey, as you would expect any corporate hotel event to be. Little 8oz. liquor and colas will come with EXACTLY 1.25 oz. of alcohol and cost around $6, I believe.
2) The Grand Manse. I have to plug this one, as I was their head bartender last year, lol. Caddy corner (To the SW) from embassy, you'll see a fenced off area to the north of what is the old federal courthouse (Big old brownstone building). It's open to the public and run by some very good bar owners. No cover charge, and drinks there are bigger and cheaper. When I worked there, and even visiting this season, there always seems to be a large group of out-of-town (opposing) fans who stop there. They usually have TVs outside as well.
3) If you head down to the haymarket (about 3 blocks west of downtown, go anywhere in dt lincoln and just start walking W, you'll find it

) than expect big crowds, but fun places. Brewsky's (American-style sports bar) and Buzzard Billy's (casual Cajun dining) are always good, but they will be crowded. They have large outdoor seating areas, but unless you get there early, don't expect to get a table anytime soon. There's a new little bar tucked in just west of Old Chicago (Which is on P) called Tavern on the Square, good prices, good outdoor seating (with shade), but no food. I usually make a point to stop there at it is generally not too crowded.
4) If you want more of the college type scene, go to O street between about 13th and 15th, that's where all the college bars are, with the expected atmospheres.
5) Misty's is always good for a steak, It's on 11th and P. Other good eats besides those already mentioned are Brix and Stone (Which is on Q, just west of 9th, heavy american dining), the N-Zone (8th/Q) and the Watering Hole (13th/O) Both serve great bar food, especially wings. JTK (7th and M) and Dish (11th and O) are both upscale steakhouse/american dining experiences. The Blue Orchid (Backside of the Grand Manse, mentioned earlier) is a wonderful little Thai place that I have to plug, even though there's no 'gameday' atmosphere there, which could be good and a nice respite from the loud and rowdy tailgates going on, especially if you're in town for more than a day.
Hope you enjoy your stay!