Fun activities in Los Angeles for natives who have done it all??

We are looking for activities for our family- we have older teenage boys who are not yet 21. We have done it all! We have done all the museums, beaches, gardens, shopping, libraries and aquariums and all the cities nearby including San Diego, Santa Barbara, Palm Springs etc. We have done ATV riding and skydiving. Kids are home from college and we are looking for something interesting and unique to do with them. Ideal would be day trips but it could be longer. Anyone have any ideas? I'm all out of them. Thank you so much!