So this would actually kind of depend on when and where we are talking, but for our purposes lets narrow it down a little.

Lets say we are attending one of the major college football games in the 1898 or 1899 season, be it maybe Harvard-Yale or Michigan-Chicago. Both represent some of the premier annual games of the era from the parts of the nation that football had been most developed and taken to. The Eastern powers still dominated the sport after spawning it but the Midwest had started demonstrating that it could play big boy football though it would be several more years before games between the two regions became the norm, while 1898 would see the first two players from the Midwest(one each from Michigan and Chicago) named to the All-America team by Walter Camp and Harper's Weekly.

But games in both, and increasingly the South and West Coast, were becoming big time events, attended by 10's of thousands, followed by even more in the hometown, with wire reports and even live updates being followed in early play-by-play calls. Stadiums like the Yale Bowl seen here a few years later in 1910 were already hitting the +30k seat mark. There would have been cheerleaders, bands, chants, plenty of booze, and already more than a few bitter rivalries. While the Eastern teams in that first tier(Harvard, Yale, Columbia, Princeton, Penn, Army, and Cornell) had established ties that would eventually spawn the Ivy League. The Mid-West teams had also formed an association to ensure formalized scheduling, sharing of revenue from tickets, and fair play, here then is the birth of the modern Big 10.

Now as to the rules lets get into it. By the late 1890's the scoring had become revised to try to reduce the impact of field goals vs touchdowns, now both were worth 5 points(before TD's were only 4 and in a few years FG's would be reduced to 4 to continue the trend), Conversions (PAT's) were still worth 1, and there was no 2pt conversion, safeties though were 2 pt's then.

In the decades before our game many of the now iconic parts of American Rules Gridiron had emerged, just not in their modern forms often. Each year representatives of the different colleges then playing would gather usually in NYC to discuss rules changes, though it was normally dominated by the nascent Ivy League powers. And by one man in particular, the former Yale player, coach, and sports writer, Walter Camp. As the 'Father of American Football' Camp in the 1880's and 90's is credited with the modern 7 man line and 4 man backfield, the modern snap, and most importantly the system of downs and a line of scrimmage to move away from a scrum. However at the time it was 3 downs to gain 5 yards.

One thing in particular though is that the game had still not approved the forward pass, and wouldnt until 1905-1906! So that made the game one of really just a series of option plays up and down the field. Additionally the QB had to be even more of a field general, there were still severe limitations on communication between coaches and players or officials. To avoid the danger of hand signs being stolen, and to deal with having deaf players, Gallaudet's team down in DC is credited with creating the modern huddle in the 1890's and it spreading from there so you might or might not see it.

The game would also be surprisingly fast paced! Since it literally could be nothing but 3 yards and a cloud of dust for 2-3 hours teams would routinely try to use tempo that would make modern teams like Oregon blush! For instance we have this footage of the 1903 Michigan Chicago game. In the last 30 seconds we have 3 plays run, right up there with the best of today's attempts. That game is also notable for being between 2 of the games great early fathers, Fielding Yost for the Maize and Blue and Amos Alonzo Stagg for the Crimson. Both were among the first generation of professional coaches, intentionally brought in to raise the school's profile through wins on the field and paid very well for their services. Yost was known for his up tempo attacks even by the standards of the time as well. Stagg is then credited with if not inventing then formalizing and popularizing everything from the End Around, to the Lateral, to the modern Linebacker position.

We also are lucky to have some additional footage of that 1903 game too!.

Additionally if you are interested on some more reading I would pickup 'The Opening Kickoff' by Dave Revsine who works currently for the Big 10 Network.