Depending on which weekend you might catch something next door at the
Ontario Convention Center.. For example, there is a dance competition next weekend; college expo the week after; employment super show weekend of Aoril 30th; Gun show the weekend of May 14th.
There might be something going on at
AutoClubSpeedway as well?
The
Graber Olive House is on my list of things to visit here in LA - though they close at 5:30 so not sure you will have enough time? But if the travel gods are with you my guess is you could be there by 4:30.