I used to get people with these ones...
Spell "most"
Spell "coast"
Spell "boast
Spell "roast"
What do you put in a toaster?
You'd be surprised how many people answer with "toast."
Spell "cop"
Spell "mop"
Spell "pop"
Spell "top"
What do you do at a green light?
Same deal. Lots of people will answer "stop."