One of my favorite places in LA is the Griffith Observatory. Bradford and I went there almost 5 years ago when we were dating and I was excited to go back again. We arrived at about 4PM on the Saturday between Christmas and New Year's and to say it was a little crowded is an understatement. We were shocked when we were able to get tickets to the 5:15 planetarium show. Nice to know that our record-breaking pace hiking from our car up to the observatory wasn't for nothing.
I love that the observatory does such a great job combining education with the natural beauty of LA. The exhibits are interesting and informative, the planetarium show is stellar, and the views outside are just unbeatable. Late afternoon was a really great time of day to go because we were able to enjoy the views in daylight, sunset, and nighttime. If you're ever in LA, I definitely recommend taking some time for this activity.
As you can see in the above picture, there are lots of hiking trails all around the observatory. It'd be fun to bring a picnic and enjoy an afternoon of gorgeous LA views.