I have DOS 5.0 still in the sealed box. I hopping it will be worth something someday like the old Victrola cylinders my dad used for target practice.
[CRINGE!!] I know people who collect those; they're actually WORTH something to the right person.
I have copies of MS-DOS 6.01, and Windows 3.11 at home.
I also have an 8-bit Sanyo MBC-1150 built around the Z-80 that runs CPM off of 5.25 floppies. I even have the old MX-80FT printer out in the shed. In the original box, yet.