Revellers took over the bars, sidewalks and even part of Ossington Avenue on Friday night during a block party commemorating the massive blackout that left much of Ontario in the dark six years ago.

Organizers say 28 venues between Queen and Dundas Streets invited their patrons to party in the dark.

"Some bars will book bands, others will have guitars to pass around," says a posting online. "No lights, no mics, no amps, no lack of good food, drink, music and conversation."

The post also suggests parking metre parties, in which one pays a parking meter in order to party in the empty space. However, people spilled onto the streets shortly after 10 p.m., blocking traffic and causing general chaos on the hip, bar-lined strip.

A massive blackout hit most of Ontario and several American states on Aug. 14, 2003. The trouble started with some tree branches touching a power line in Ohio, but it quickly cascaded across the border.

The blackout affected about 10 million people in Ontario and 45 million in the U.S. Power came back on in some parts of Toronto within 24 hours, but in other areas, people were without power for several days.

Officials say there's no guarantee a similar blackout couldn't happen again, although various measures have been put in place to avoid one. They include regular audits of the various power companies involved to ensure maintenance standards are being met.