I've been extremely tardy about setting this up, having lived here for 12 years already, but decided I don't want to watch the Euros alone and finally got my finger out.
I've set up a Facebook group to try and coordinate watch parties and events (if there are any) across the city.
https://www.facebook.com/groups/593429824967863
Personally I am based in Ventura County so have a bit of a north-LA bias, but happy to coordinate folks all across the region.