Yes, yes, yes, yes, LA, and yes, yes, yes, yes, yes in anticipation of other questions
I'll keep a running list here because I know I'll think of more every day
If you like being active hiking and biking . Rent a bike and rid on the beach trail stretches from Santa Monica to Palos Verdes, about 20 miles (so 40 miles RT if you want to do the whole thing). the San Gabriel mountains are incredible for hiking but recent fires might put the kibosh on those for this year I'm sad to say. There are good in city hikes in Griffith Park, Will Rogers St Park, Malibu
Speaking of Griffith Park the Observatory is an iconic LA building (you've seen it in many movies I'm sure) and clear weather willing the views of LA are very nice. The LA Zoo in Griffith is not as nice as San Diego's but its still nice
If you like walking through botanical gardens Huntington Gardens in Pasadena is definitely worth it, including more of the iconic roses than you've probably ever seen in one place
Museums. the big one is the Getty Center sits high up on a hill in Brentwood. Great architecture. I'm not a big art museum guy but if you are go to town. I think the Getty Villa in Malibu is better . Believe reservations needed for both. if you are staying near the Coliseum Science Center is great but the main attraction is the space shuttle which is awesome to see but its temporarily closed as they move it :(. People I know love the LACMA (again not a art guy !) .
I didn't agree much with mildones post about LA but hey different strokes, right? the one thing he's right about is Hollywood. Should be avoided with the notable exception of if you are a movie person seeing a flick at the famous Chinese Theater is an iconic LA experience and would recommend .
As far as avoiding things--downtown LA which is near USC. Quite honestly very little to do here.
Also for movie buff, the studio tours are generally very cool (I'm not including Universal which is a theme park). But Paramount, Warner Brothers and Sony tours were fun but havent been to these in a long time
I think the NFL is happening that weekend but if you can manage a tour of SoFi stadium I would highly recommend as its like nothing you've ever seen if you like stadiums.
Drive up the coast to Santa Barbara for a day trip on the Pacific Coast Highway, great views on the drive, Santa Barbara is mostly a lovely town
if you want beach town vibes, drive (not too far) to Manhattan Beach and take a stroll on the Strand. MB is my favorite LA beach town. Beach volleyball, countless 8 figure homes. Lot of athletes (both LA atheletes and others that live here in off season can be seen here Good food here too. The scenery here is impressive as well (yes my wife knows and accepts me)
if you like shopping of course Rodeo Dr in Beverly Hills is a favorite. Century City Mall is nice too
I saw someone mention going to Catalina. this is guaranteed to an all -day affair so you can't just pop in to check it out. The ferry takes a minimum of an hour each way and it can be a little rough. It is a cool place, very much not L.A-ish
If you like horses/thoroughbreds Santa Anita (home of Sea Biscuit) is a fun place to spend time
if you aren't afraid of some bohemian weirdness take a walk on the Venice Beach boardwalk (yes, it's perfectly safe) home to the well known muscle beach gym made popular by Arnold as well as the "White Man Can't Jump" basketball courts
Avoid star home tours at all costs. Pure rubbish
Food --I might not be the best person to ask since I have what is known as a sensitive palate, a.k.a I'm fussy AF a.k.a a real pain in the ass as George Carlin said. I do not like sushi which is like sacreligious here in LA so might want to ask some others about that. I have my favorites though which I can always share, but LA is freaking huge with more choices than you can possibly talk about. I generally enjoy eating in Pasadena, Santa Monica, Beverly Hills, Manhattan and Hermosa Beach, all great dining destinations. If you think you find something you like make reservations like NOW. The popular spots are exceedingly difficulty to get reservations for
Yes traffic sucks. Take into account driving times. avoid freeways at rush hours (duh) Waze is incredibly and eerily accurate with driving times.
Assume you need to reserve everything in advance so look up crap online well in advance
I'll add more as I think about it.