Does he like me, how should I ask him to a movie?

This really shy boy I like at school, he sits across from me at lunch. A week or two ago he was acting kind of strangely, little did I know my "friend" told him I thought he was cute. She said he replied with a smile and said "no she doesnt!". I didn't know she had told him at the time and he had kind of avoided me for a while, but then I moved over by him and started talking to him more and said yes, I do like you. And he is starting to get a little more comfortable with me. I took his notebook and wrote in it and he took mine and wrote "this is for stealing my planner" and scribbled. On thursday he asked me if I was going to the game on friday, and I said oh i dont know, and he replied with ....oh im not going. and whenever i talk to him he smiles... do you think he is into me, i also have his number. i gave him this little booklet that people write their numbers in and he wrote his name and smiled and said "just name" and kept smiling at me and so i asked his friend while he was sitting right by him and he said "no ____" jokingly then said just kidding haha, it doesnt matter. did he not want me to have his number or was he just playing around? i want to ask him to see the horror movie "the step father" with me, is this a good idea, and in your opinion, is he into me? i really like him... How should I approach asking him to the movie?