As far as "official" OGR functions go, there are two:
Thursday evening: The "Thursdays at Fridays" get together. Starts whenever the first folks get there (around 6, usually, or maybe even a bit earlier if you want a good table) and ends when they lock the joint up.
Friday at 2 p.m.: OGR Forum Members (and anyone else who cares to attend) meeting in the Grandstand. Presentations by various manufacturers and whatever else may come up.
A group of Jewish forum members hold an informal get-together on the fairgrounds at around 10 a.m. on Thursday, before the meet opens at noon, wherein Kosher foods of various types--along with cigars --are enjoyed amidst friendly discussion. Gentiles (like me) also welcome. This event takes place adjacent to the parking area just past the far end of the grandstand (the end of the grandstand closest to the Highland Ave. Gate)