I liked "Mars Attacks", but I also liked "Killer Clowns From Outer Space" and that great movie where the kid gets to fly the flying saucer. (Help, Mars! - The saucer had the fluid steps!) And also that movie where the two kids build a space ship and travel up to the mother ship and meet the little kid space creature who is hiding from his father. (Sounds like crap but it was pretty good.)
Each of the above was pretty darn humorous and done well.
You all have not seen it yet but I think you'll be enjoying "Skyline" soon.