What are some uncommon but valid portmanteau words that people use?
Example: Turducken is a portmanteau of turkey, duck, and chicken or hen. People outside US are not familiar with this.
Here are a few that have entries in the Merriam-Webster Online dictionary:
Lewis Carrol made this into an art form. One of my favorites from "Alice in Wonderland" was "Frumious" it is a combination of "Fuming" and "Furious"
The crocoduck denotes an hybrid animal with the head a of crocodile and the body of a duck, which became recurrent in debates involving creationists and proponents of evolution, being used as a symbol directed at those who do not understand the basic principles of evolution.
Webinar: web + seminar.
Philanfatique (What your hosts get when your evacucation runs long)