Translation:I was invited to the crayfish party.
I'd always imagined it'd be like eating miniature lobsters. Hot, maybe boiled with lots of Old Bay seasoning and served with melted butter. No. No.
Kräftskivor teach us why we fear the dark. What might well have been tasty in other circumstances has been transformed into little devil nightmares on a well-decorated serving platter. Cold as death, they have plainly been stewing for weeks in 100 proof formaldehyde. You crack them open with your teeth and suck the so-called "juice" out from the underside of the thorax. Eventually you grasp your host's repeated suggestion that you remove the "tråd" (or bajstråd) before eating the tail, but alas, det är redan lite för sent.
You politely remove yourself to the bathroom not once, not twice, but three whole times during the course of that evening, but for no reason other than just to try to scrub the förbannad "juice" stink from your hands.
Finally, smiling and waving good-bye to everyone at the end of the evening, you keep the car window rolled down all the way home, wondering if you have enough other clothes there that you maybe could just burn the ones you have on.
What's the difference between 'Jag blev inbjuden' and 'Jag var inbjuden', and generally the difference between Jag blev and jag var?
Jag blev inbjuden means that somebody was performing the action of inviting you.
Jag var inbjuden means that you were in the state of having previously received an invitation. The phrasing may also imply that even though you were at once point invited, you are no longer invited.
That's the general gist of the difference as well, but of course, idiomatics may vary and the best translation might occasionally differ from the most literal one. :)