It's basically a glorified camp.
Here is a nice rundown of the invite they send to prospects, which gives you an idea of what they do and what is expected:

http://grfx.cstv.com/schools/osu/camps/graphics/m-footbl-friday-night-ca...

It's pretty fun, I've been there every year so far. It is a camp, it is free and open to the public, and it is at the 'Shoe. You'll get to see commits, along with a lot of highly rated recruits compete. There are usually many current players that attend as well. And they play cool pump-up videos on the big scoreboard screen.

For example, last year EGW and Damon Webb put on a show for everyone going against each other. EGW had the crowd pretty fired up. Another highlight was Braxton Berrios, whose performance earned him an offer.

Definitely go if you can!