Staying at the Sofitel in Beverly Hills for three days in mid August......What to do for a first timer in LA?

You'll have to throw us a line here, Steve, by telling us what your tastes are.
When this type of open ended question has been asked before some people write back with recommendations for cultural enrichment theater, La Brea tar pits tours, and tours of the neighborhoods of the Stars.
Obviously the recommendations could be all over the map.
Museums?
Sports?
Beaches?
Shopping?
Live music?
Theater?
Touristy things?
Hollywood?
Disneyland?
Boating?
Gourmet cuisine?
Film studio tours?
Will you have a car?

Best thing to do in LA? Take the boat over to Catalina. Beautiful!

Go to the Getty --even if you are not much on museums.

Another vote for the Getty. I grew up in LA and now just go to visit relatives. Last year I finally went to the Getty and wondered why I hadn't gone before. It is really a must see - the architecture and the view. The art is good but overwhelmed by the architecture.

Also, if you like hiking, hike up Mt. Baldy. Santa Monica is interesting - walk along the beach.

My favorite area is Santa Monica (the pier, 3rd street prominade). Venice Beach is also interesting to visit. Griffith Observatory has a great view and you can also see the Hollywood sign from there.

Have a great time. I went in February but I wish I was going again this year!