An Israeli lawmaker has proposed to place a price ceiling on popcorn at the movies. Via Chris Tozzo
The relevant question that should be asked is "why does popcorn cost so much at the movies (and at sports stadiums for that matter) in the first place?" Paul Walker offers a nice discussion of some of the theories that have been proposed for this seemingly simple but actually complicated pricing scheme.
Another relevant question is "how will movie houses respond?" Will they increase ticket prices, offer fewer concessions, or something else? There is theory and evidence in the sports economics literature that high concession prices are part of the reason why sports ticket prices are priced below what economists expect a profit-maximizing team to charge. See here and here for examples. This suggests that there is some funky bundling going on.
I've offered another possibility for why ticket prices are low in this Applied Economics article.