Yo OP, I'm gonna be straight with you: as a LA native who has recently begun checking out all the sights and sounds of LA these last two years, there's many great places to explore (skimming through this thread, I wholeheartedly endorse the Museum of Jurassic Technology, the Broad, the Bowl, the Edison, Angel City Brewery, and Marugame). Typically avoid Hollywood since it's a tourist trap with overpriced stuff and shitty parking, the experience is quite hollow. But there are two places that absolutely top my list that I can't recommend enough: The Getty Museum and the Huntington Library. You could spend the entire day walking around the exterior of the Getty without ever actually seeing any of the fantastic art. The view of the city it provides as well as it's storied architecture are worth the price of admission alone.
As for my second recommendation, I know what you're thinking: "A library? How great can a library be. I don't want to spend my limited time here checking that out." Do NOT dismiss it based on its name. The name is deceptive. It's not actually a library -- it's a MASSIVE botanical garden, that's divided into different sections based on the region of plants (ex. the Japanese section has a giant sprawling garden with hills, waterfalls, stone bridges, and a bamboo forest you can venture through -- imagine this but for like 10 other unique sections.) It's honestly like a botanical Disneyland. You don't even need to like botanical gardens or plants all that much to enjoy yourself. The place is an absolute blast and you can spend the entire day here and still not see everything. It's honestly one of the best places in LA.