Sesamoid Street
A spin-off of Sesame Street devoid of all gaiety and featuring such mirthless characters as Pisiform, who is, not unjustifiably, referred to as "Pissy-form" by his cross-town rival Patella in an obvious allusion to Oscar the Grouch.
Despite critical acclaim from the medical community, Sesamoid Street could not find its place on TV as it struggled to find acceptance among the key kindergarten demographic.