I love US coins and mint sets that boggle the mind, uncommon types, or radical forms, etc. Things like the SMS sets from the era of numismatist animosity from the mint, or the two-cent, three-cent, and twenty-cent denominations that sputtered out, or perhaps the enhanced uncirculated set the mint did a few years back to celebrate the philly mint's 225th anniversary.
Anyhow, two questions on this subject;
1). what are some other radical mint sets and coins?
2). Would you consider the reverse proof sets to be among this genre?