Weevil

Best answer as chosen by Asker / Ratings
The Hyman Memorial Stadium is open only between a certain time. I think it's between 9pm until just before midnight. The door is at the top of the stairs.
When you enter, depending on which billboard is up, you get to enter the Blood Ring, race a circuit, or ride an obstacle course on a Sanchez.

As for properties, I only can remember a few. Best bet is to check the map that comes with the game to see where the properties are.
On the left side of the island, there's the Hyman Condo (near the Stadium), Shack (go up stairs near biker bar), Print Works, Cherry Poppers, Kaufman Cabs, the company at the docks, and the car showroom on your way to the airport.
The right side of the island has El Swanko Casa (near hospital near Prawn Island), Vercetti Estate (Starfish Island), Oceanside Hotel (default), The Malibu, The Pole Position (near your hotel), the house near the pole position, the house near the golf course, and the Film Studios on Prawn Island.