One of the rarest sports cars in history is up for auction at Bonhams: the 1969 M-505 Adams Brothers Probe 16. Only three models were ever made, and all three units are still around, though the location of one unit (chassis number: AB/2) is unknown. Meanwhile, one of the three units can be yours, provided, of course, that you have deep pockets to pay for it. Bonhams estimates that this example of the M-505 Adams Brothers Probe 16 (chassis number: AB/3) will fetch anywhere from $150,000 to $250,000.