I start off by saying a decade and a fad from that decade. Then the next person has to pick the decade before it or the decade after it, and tell a fad from the decade you picked. I'll start with...

90's Furby

Now you can pick the 80's or the 2000's (2000-2010)

80s: Miami Vice's type of dressing.

And now tell me a 70s fad.

70's Dead Kennedys

You can do the 60's or 80's again.

The 60s: Being a filthy Hippie

Lest go with the 40s.

I can't do the 40's. Since you did the 60's I have to do the 70's or 50's.

50's Elvis

60s Beatle Mania

50's duck and cover

tasteless, but all I could think of.

EDIT: you can do 60's or 40's

40's

World at War