Found via Wedinator, a thread on Reddit starts with
A friend of mine has been talking up how cool his wedding invite is for weeks.....finally it shows up...
[Parents] Invite you to share in the joy of the marriage between their children Elizabeth and Christopher, November 6th 2010. Lawn of The Picnic House, Prospect Park.
The original poster has deleted his account, but from the comments it seems like it's not a real NES cartridge, and they could use a graphic designer, but we'll give them points for geekiness. I also like this comment:
Thank you Christopher! But Elizabeth is at another Picnic House!
I'm not sure if I should roll my eyes or laugh, so I'll do both.