Minecraft is such a great game in my view, it allows you to use your imagination and have fun with it.
It reaches out to all ages, and believe me, all ages play it, from 6 year olds to 60 years olds( i know a 60 year old who plays it and shes AWESOME AT IT)
The simplicity of it makes it great. You can make rules and game modes how ever you like! It's awesome.
It's like making your own game but with out the complicatedness of programming.
I also believe the funny look of it attracts people, i love the 8bit look of it,
I truly believe it's worth the 25 bucks