That's call 'sheet' lightening that is.forked lightening between clouds !
Lol, no, seriously, these were streaks of lightening going sideways !!! an awesome spectacle !!
Yes. Not unusual, though. Earth to cloud lightning is less usual, but the one I'd really like to see and never have is ball lighting. They still don't know what it is.
I think it's God throwing fireballs at us for being naughty!