An analogy is a comparison between two different things, in order to highlight some form of similarity. Here's are a few of mine in regards to Linux compared to other operating systems:
MUSIC:
Unix = Classical Music
Linux = Jazz
DOS = Polka
MAC = Blues
Windows = Rock-n-Roll
Vista = Hip-Hop
CARS:
Unix = Dump Truck
Linux = Porsche 911
DOS = Moped
MAC = Subaru Outback
Windows...