An attractive female model hired to give presentations/demonstrations at a trade show, especially in high-tech industries where the audience is predominately male.
The newer synonym booth babe has largely replaced the less politically-correct 'booth bimbo'. However, booth babe only implies that the person was chosen for the role because of their appearance (but could actually be an employee of the presenting company rather than a professional model), while 'booth bimbo' adds the connotation that she has simply memorized a script and is totally clueless about the product.
I was so mesmerized by the booth bimbo that I actually asked her a technical question after the demo, thereby embarrassing both of us.
Nobody was checking out the WhizCo exhibit - if they couldn't afford a booth bimbo, they were obviously minor players.