Ellen Muth's name that she goes by at Happy Time is 'Mildred' of which Delores asks if she can call her 'Millie'. This is a reference to the Piers Anthony character in his 'Xanth' series of books, Millie the Ghost. The premise of the show was also inspired by the Piers Anthony book based in the same world entitled 'On a Pale Horse'.
At one point in the episode, George refers to seeing her family without her is like being in an alternate universe where she didn't exist and that there were no goatees or gold lame sashes. This appears to be a reference to the original Star Trek TV series episode "Mirror, Mirror" where in the alternate/parallel universe the character of Spock has a goatee and the crew wears gold lame sashes as part of their uniform.
DVD box-set includes a deleted scene with C. Ernst Harth as Obsessive Man, a guy addicted to mini-waffles driven to killing the owner of the restaurant they come from as the only way to beat his addiction.