popcorn... well for eating... candy for imaginative play...
as to the difference per the Grammarist
http://grammarist.com/spelling/theater-theatre/
"In most contexts, there is no difference in meaning between theater and theatre. Neither has any special definitions in general usage. The main thing that most English speakers and learners need to know is that theater is the preferred spelling in American English, and theatre is preferred virtually everywhere else.
Some Americans do make distinctions—for instance, that a theater is a venue while theatre is an art form, or that a theater is a movie theater while a theatre is a drama venue. There is nothing wrong with making these distinctions, but they are not consistently borne out in general usage. Even in 21st-century writing on the art of theater, the more American spelling now appears for all senses of the word."
and ending that little side track of a thought...
The itch of adventure at a drive in...
Do you do it in the dark confines of rear rows..
Or find a secluded spot up front with the risk of discovery.