Summary: The crew of moon mission Apollo 13 encounter problems in space, and spend a harrowing week attempting to get home in one piece. This REALLY happened, kids!
FANTASTIC film. The space effects are awsome. Almost NO historical or technical errors whatsoever in this film except one: I hear that Jim Lovell's corvette was blue, not red. :-) A definite MUST SEE!!
I would also recommend watching the NOVA special on the Apollo 13 mission: it gives a lot of background and shows the actual events as they occurred. Watch out for the "square peg in a round hole" scene where Ground Control has to rig up the CO2 filters: it's exactly like that in the film!
Further Info (IMD)