I forgot about all of those, save for Weird Science, and had to IMDb it to believe you. I think a lot of people probably only knew as much about him as I do; that is, don't know he was a writer, and only knew of his directing career. He wrote for all of those, but didn't direct any National Lampoon movies. He also wrote the entire Home Alone series, the Beethoven series, Miracle on 34th Street, Baby's Day Out, The Great Outdoors, and Dennis the Menace.