Javier Martinez uses a sign to advertise for LoHi Cannabis Club
dispensary as an estimated 10,000 people were expected to gather
for a 4/20 marijuana rally Javier Martinez uses a sign to
advertise for LoHi Cannabis Club dispensary as an estimated
10,000 people were expected to gather for a 4/20 marijuana rally
in Civic Center Park April 20 in Denver, Colorado. (Marc
Piscotty)  DENVER — When Chuck Blackton opened his medical
marijuana dispensary in 2009, neighbors included a check-cashing
business and a dollar store.  Now, a sushi bar has moved in a
few doors down, and a new deli grocer across the street offers
canned escargot and Niman Ranch corned beef sandwiches. A magnet
on the espresso machine at the Amsterdam CafÃ©, a neighborhood
hangout, declares: "Marijuana: Not just for hippies."  Blackton
sees his stretch of Denver's Colfax Avenue as upwardly mobile.
He and others who've striven to make their dispensaries look
like something other than tattoo parlors are saying marijuana is
for yuppies — and everyon