Patented D20's?
I can't quite remember who told me that Gary Gygax patented the d20 dice. In any case, if it were true, that patent may not hold up anymore given the link here.

It's a d20 used by the romans up for auction at Christies. Cool, no?

Location New York, Rockefeller Plaza
Sale Date Dec 11, 2003
Lot Number 189
Sale Number 1314
Creator Circa 2nd Century A.D.
Lot Title A ROMAN GLASS GAMING DIE
Estimate 4,000 - 6,000 U.S. dollars
Pre-lot Text THE PROPERTY OF A MARYLAND FINE ARTS PROFESSOR
Lot Description A ROMAN GLASS GAMING DIE Circa 2nd Century A.D. Deep blue-green in color, the large twenty-sided die incised with a distinct symbol on each of its faces 2 1/16 in. (5.2 cm.) wide

Provenance Acquired by the current owner's father in Egypt in the 1920s.

Lot Notes Several polyhedra in various materials with similar symbols are known from the Roman period. Modern scholarship has not yet established the game for which these dice were used.

Got this from www.pvponline.com.