The Gods Must Be Crazy. I saw it long ago and loved it. I went to youtube to see if it was there and yep...quite a few people have uploaded it. Just find the one that has the best viewing cuz some suck.
Wow, I thought you meant OLD movies. The Gods Must Be Crazy isn't really an OLD movie to me, but I guess it's a matter of perspective. One of my favorites from that era is The Jerk with Steve Martin.
From the 60s, one of my favorites is It's a Mad, Mad, Mad, Mad World. You get to see all the greatest comedians of that era and it's a fun story. Vertigo with James Stewart is my favorite 'serious' old movie. And my favorite REALLY old movie is Grapes of Wrath.
Now... If "old" means not recent... There are a ton of movies I like to watch and could watch a million times and never get tired of them. Goodfellas, Reservoir Dogs, Pulp Fiction, The Big Lebowski and a quirky little offbeat movie with all three of the Wilson brothers called Bottle Rocket. Oh... and anything with Clint Eastwood.
One more to mention that I missed previously is a movie from the 50s by Lucy and Ricky Ricardo.. The Long, Long Trailer.
Casablanca is probably the best movie ever made. Not sure there is a better scene in all of cinema than Paul Henreid leading the band in La Marseillaise. Guess Who's Coming to Dinner is likely a close second. There are a couple of "throw away" scenes in it that keep it from being the best ever. The Magnificent Seven is likely the best western ever made. With a cast like that, it could have easily been a disappointment. They all shine.
Not sure if musicals are your thing but I think that Grease is probably not given enough credit for delivering joy for two hours. Stupid ending though.
Movies from this era that should not be overlooked are: Unhook the Stars with Gena Rowlands, Moria Kelly and Marissa Tomei Rachel Getting Married with Anne Hathaway. Crash with Don Cheadle, Brendan Fraser, Sandra Bullock, and a cast of thousands..... Heat with Deniro, Pacino, Kilmer, Sizemore, Azaria, Ashley Judd, David Fincher, Jon Voight, Tone Loc, Mikelty Johnson; gripping, gritty, and gorgeous.
I was watching an old John Wayne movie last night (bought a 20 movie CD box) I didn't realize most were made in the 30s I thought he came along in the 40s ..