Can Two People Hallucinate the Same Thing?

It's ticket time for lots of fall/winter events--Day out with Thomas, Imagination Movers in Concert, North Pole Express at the Essex Steam Train--and we've been discussing and debating what we want to do this year.

And we are completely perplexed: Mama and I swear that we took the kids to the special Christmas edition of the train ride in Essex a few years ago. But we can't find any proof--no blog, no journal entry, no pictures, no email, no receipts--that we did it. Except we both have memories of it: of packing special cookies because the kids were still gluten-free; of getting the special little bells from Santa even though the kids would be too young to play with them; of seeing the decorated train cars and hearing the songs and stories; of going back to enjoy the ride with the kids after having gone when I was pregnant (on what was the most "morning" sick day of the whole thing). But, then, where did we eat lunch? Or, if it was an evening train, what were we doing out, when we almost never took the kids out after bedtime? Where was the stroller, which we always traveled with? And finally where was all the evidence? Did Mama forget her camera? Did I forget to journal or blog it? Did we tell anyone else about it (did we?? help us!). Have we invented the memory from a combination of the Christmas train ride we took when I was pregnant plus the times we've gone out to see Thomas?

Please, if you have any insight into this, help us! It was probably either 2006 or 2007. And it's driving us nuts . . .