Well if you live in Mexico you can (sort of)
A fan sent these pictures in to Mexican Twilight site Crepusculo Meyer, who added the details of the promotion. RobPattzNews translated them :
In each Corn Pops box you will find a free ticket to watch Eclipse in theaters. The ticket is valid Monday through Friday. Check restrictions on the cereal box.
Thanks to Crepusculo Meyer and RobPattzNews