let's say there's three big families: major, minor, and diminished...
That means that starting on a c, you 'll get 3 different scales (major would be cdefgab)
minor implies a flatted(one half step lower) third, which gives it a "sad" flavor...
As for diminished, the third and the fifth are now flatted...The flavor is then tense...

Starting form those, you can now change the spots of the other intervals around... FOr example, a major scale with a raised fourth will be what we call a lydian mode... Of course, the possibilities are endless, as you can have 5 notes scales (pentatonic, it's a minor without a third or a sixth)6 notes (with the blue note) etc... up to the 12 notes scale, which is a max in our system of tempered music (it's called the chromatic scale)