If you're a Goodwill or thrift store shopper, I'm sure there's at least one very strange thing you have come across. Feel free to post photos of oddities or share your stories. To kick things off, this thing is truly baffling.
That elastic band display is amazing! Not in Goodwill but in my local charity shop back in the UK about 20 years ago, the old ladies who ran it set up a pool party display in the window of about 20 naked Barbies and one naked Ken. I still have a photo of it somewhere, will update if I find the pic.
I found a burnt copy of Tomb Raider for the Dreamcast on a CD-R with some day in 2004 marked on it. Thats about all for Goodwill. Kinda sucks.
Nothing amazing - I did find a DTL-H1001H with a bad CD drive in a charity shop in Victoria BC and a Black Xbox 360 HDDVD drive in a Goodwill in Seattle (apparently the black cased ones were only available as MS internal giveaways).
I'm not sure if this counts, but I find my local Goodwill's lack of quality control to be pretty entertaining:
One time I found Virtua Racing for Genesis. My local one seems to be a haven for broken ukuleles. There's more every time I go back there (they're at around 6 total now, none in working order) They say it is where tv commercial music goes to die