In many ways.. you can create an impressive collection of just about anything. With the right display cases and thorough research for the strange and extraordinary, anything can be of value.
There are many alternative travel guides across America or Europe, for those who cringe at the sight of galleries or museums there's certainly something for all walks of life...
Here are a few odd ones...
Antique Medical Equipment
Perhaps it doesn't sound strange when it's only medicine bottles, syringes and vials... but when one sees the saws, bone chisels etc... your imagination can't help but runaway with you. (More info on museum of quackery... I'd also say the Museum of antique handcuffs run under this strange peccadillo)
Air Sickness bags
A few years ago Virgin Airlines hosted the "Design for Chunks" design competition that showcased 20 winners who had their artwork appear on sickbags on Virgin Atlantic flights throughout the world.
Ship beer bottles: Who would've thought all those things you toss out in the dumpster would be treasured art?
The Labyrinth of Buda Castle, Budapest, Hungary
The Leprosy Museum, Bergen, Norway
Cern Abbas Giant, England
Frog Museum, The Hague, Netherlands
Museum of the Souls of the Dead, Rome, Italy
The Absinthe Museum, Paris, France
Museum of Miniatures, Andorra, Ordino