Men In Black was the surprise hit of the year, mainly due to the fact that all the "Summer Blockbusters" were either too chicken to compete with other releases or too crap even for the studio's generated hype to drum up business. A short, snappy little number, Men In Black pairs up (Will) Smith and (Tommy Lee) Jones as the secret government agents that oversee the activities of  real illegal aliens, that is, tourists from other worlds. 
It's attempt at plausibility works well, most aliens can cunningly disguise themselves in human form, and any unsuspecting soul who inadvertently comes across such a being in it's "natural state" can receive a memory wipe, thus dealing with any associated trauma. Earth seems to be a popular place to visit and in general the aliens are well behaved. However, there are always some irritating tourists that give the rest a bad name and one has decided to run riot in someone else's body. Add the mystery of a missing galaxy and things start to get strange...
So, the day has to be saved and there are only two men qualified to do it. Cue the visual gags (particularly where aliens are concerned), hi-tech gadgets and military hardware, with time for some (but not a vast amount) of love interest. Narrative is not an issue here, there's no need for any deep meaning philosophy; it's simply a licence for the film- makers to go mad with their imagination and humour. Which is basically what they did.
The concept was good and the film was enjoyable to watch, but bearing in mind the material available, could have been quite a bit more manic. It suffered from a very fast paced trailer, which gave away all the best jokes and indeed the ending.