For those playing along at home, I will now remove the shroud of mystery surrounding Luke and the backpack items of questionable circumstances. Dad, you were very close.
1. Gunnar's dad came in to talk to Luke's class about working at the airport and the souvenir he gave out was from a deck of cards featuring airports of the Greater Midwest.
2. Meet Evan, otherwise known as 'Grimace', who was Luke's kindergarten book buddy.
3. Luke's dry eraser sock, for when he was practicing math on his individual dry erase board.
I threw the sock away and I am not sure where the four of diamonds went, but Evan is gonna stick around for a while. That guy just makes my day :)