WarGames (1983) 
As some of you may know from another thread I'm currently reading
Ready Player One which is a fantastic love letter to the 80s. A pivotal scene in the book centres around Matthew Broderick and WarGames, it was such a good chapter that I dragged my copy of the film out and watched it again.
American cold war teen-thriller with an anti-war stance that seems quite out of place with Reagan's America that's exciting and action packed!
I've not watched this for a while, and the first thing which struck me was how young Broderick looked so I checked his Wiki page and he was 21 when made this, and therefore 24 when he was Ferris
to say I was surprised in an understatement lol
Oh yeah, Ally Sheedy was cute too (also 21.., also surprised!).