Weird meeting with neighbor ... NWR ...

So I am home last night and around 8:45 the doorbell rings. I go downstairs and answer it and find two women I have never met at the door. The younger one says she is my neighbor, and points to the house across the street, and that they are having a party and would like to invite me. The invite is in her hand. I figure it's a Tupperware or Pampered Chef kind of party, so I say, Oh, ok, how nice, it's Jennifer. She then asks for my last name, and I say, Oh, I don't like to give that out. The older woman, her mother, writes my name on the invite and hands it to me. The daughter then says the party is for her mom and dad, it's her mom's birthday and the parents' anniversary.

How weird is that? Why would I go to a party for someone I have never met? Plus, the mom doesn't even speak English. So if I went, I wouldn't be able to communicate with her! And why the hell would they need my last name if they had planned all along to give me the invite right then and there (like they did)? That part freaked me out.

I was wondering why they would invite me. Maybe I waved to them once or twice while I was walking the dog, pulling out of my driveway, etc. Are they fishing for gifts? Do they not have any friends? I think it's the latter, in which case I feel very bad for them, but I think it would be more than awkward to go to a party for someone I do not know.

Do you think I even need to give a card??? There is a phone number on the invite for me to RSVP to ... I planned on putting a card in the mailbox this week and just writing in it, 'Sorry I cannot make the party.'

Is this not the oddest thing you have ever heard???