i agree that both getty collections are not that interesting, but both are definitely worth it for the architecture/views.
for actual museum-going i'd also suggest LACMA and MOCA, both have some pretty fun exhibitions going on now too (tim burton in lacma and street art in moca). even if you're not a huge academic arty kind of person, those exhibitions are super accessible.
i don't know why the obvious hasn't been stated, check out the beach communities ;)
- venice is a favorite, both the touristy (but still really crazy and worth checking out) boardwalk, as well as abbot kinney... the galleries kind of suck but there's a lot of good food and great design shops, awesome cafés, etc... also worth checking out the canals, which are pretty cheesy but also pretty awesome. lots of crazy architecture. venice is probably one of my favorite neighborhoods in LA (but i'm biased, i grew up around here lol).
- grab a bike / longboard and ride along the beach up to santa monica (to just poke around and see, maybe check the pier out. it's not super interesting otherwise, unless you're into super generic upper-middle class commercial playgrounds. then check out 3rd st. promenade.) you can even keep going further up north to the gay beach (explained later), it's all a very nice ride.
- or you could bike south, a great trip is to go all the way down to san pedro, get some great fresh seafood and beers, bike back up. this takes a while though.
of course there's the "gay beach" north of santa monica (ginger rogers), if you want to see a bunch of typical LA fags in speedos on a mediocre stretch of sand, you can go there. free parking on the street is a plus, though if you go a little further north to temescal canyon, there's also free parking there and the beach is nicer. and you won't be subjected to listening to shitty gay dance music.
if you go even further north, past zuma, that's where all my favorite beaches are... it's a long drive but really worth it, i love going up there. you're gonna have to PM me for more specific info though since i don't want to burn them out too much
hiking is also amazing in LA. there are a bunch of trails in the santa monica mountains, not far from the PCH, which offer amazing views of the ocean, cliffs, lakes, etc.
if you're more of a forest and river kind of guy you can check out the national forest hikes, really beautiful with pine trees and waterfalls... all within a 45 min. drive from LA...
runyon canyon is actually a really stupid and lame trail, but i think it perfectly wraps up the LA experience... you'll be hiking next to anorexic blonde fake-titted-and-tanned trophy wives in designer sport bras, douchey but incredibly hot shirtless wannabe actors with six-packs jogging with their chihuahuas, and execs talking loudly on their cellphones about multi-million dollar deals... with the constant hum of traffic and sirens in the background... all against the backdrop of a seriously perfect view of the entirety of LA, from the hollywood sign, to downtown, century city, the beach, the mountains...
there are three main ways to get to the summit: a shitty, boring, concrete fireroad; a shitty and short/steep trail; and then the least shitty of the three which is just to the left of the fireroad trail.
for going out, i'm very biased towards the silverlake scene. i guess you could call it a little more indie and chilled out. malo's taco night is a favorite of mine lol (straight). akbar is a lot of fun, MJs too. just depends on your taste though... if you're into overpriced covers and drinks, awful music, awful clothes, and even more awful people, by all means check out weho instead!!
moustache mondays (on mondays, duh) and mr. black (on tuesdays) are also both great, probably the only weeklies in LA i actually enjoy now.
downtown has surprisingly a lot of stuff popping up too, new galleries and restaurants/bars (wurstkuche is a lot of fun, it's like a sleek-but-kinda-hipster beer garden, amazing beer selection).
and check out cinespia! classic movies projected at the hollywood forever cemetery. big LA summer tradition.
fuck i wrote a lot. LOL. i have some friends from france visiting soon so i had a lot of time to think of this...