I went to the last glasgow open day.
Basically there are just various tables set up, for subjects in one hall and for clubs, unions, extra curricular stuff outside/in another hall. Glasgow was good compared to the other open day I have been to so far, manchester, as you are not herded through. There is plenty of time to chat to subject teachers/students and there are tours of the halls.
There also talks on the application process/student life/various subjects.
Going to open days is a good idea and Glasgow is LOVELY.
It scores points for me for having a distinct air of hogwarts about it. Likeness to Hogwarts is of course one of the main criteria I am searching for in a university (I am only half joking).
There is a cool museum with loadsa stuffed things, and a plane. A nice park. River. Botanical gardens. Shops.