I was going to say Star Trek 2-3-4 as a great adventure/comedy trilogy. Your friend may not be a nerd but these are very much era touchstones.
Also, no love for Indiana Jones? I only saw Raiders mentioned once (could be my dodgy eyesight).
A little outside your time range but Picnic At Hanging Rock (1970s)
Mad Max 2
Happy Feet (a bit later but fun)
Red Dog (also later and a bit of a tear jerker, as well as really funny, filled with Aussie humour)