The Employee of the Month Model is a woman who works at the Springfield Nuclear Power Plant as an "Employee of the Month" model.
She appears while Homer is loathing about on his boring day. She enters with balloons and the Employee of the Month Presenter to present Homer with the Employee of the Month award. She simply acts as eye candy while the presenter does his job. Homer is disappointed to find out he wins a dismal job as a chimney cleaner, where he is the actual object used for the cleaning.
In "Homer Defined", there's a woman who gives Homer awards for saving the power plant looks similar to the Employee of the Month Model.