Some visiting activists who kept a low profile during the G-20 will have their say publicly after all.

The Permaculture Demonstration Bus is a Montana-based outfit whose Skills for the New Millenium Tour (www.permibus.org) has been circling the nation since February 2008. Organizers Delyla Wilson and Stan Wilson demonstrate sustainable-living skills, including on-board gardening and composting. There's also a photo display about large-scale sustainable farming practices.

The bus hit town last Tuesday, but the Wilsons say they were subject to police surveillance that began minutes after the converted school bus pulled into its local host's North Point Breeze driveway. Last year, before the Republican National Convention, in Minneapolis-St. Paul, they say, police impounded the bus for several days but never gave a good reason or charged them with a crime.

In Pittsburgh, neighbors told them a helicopter hovered over the Point Breeze property for more than an hour the night the bus arrived. (They were not staying on the bus at the time.) And that night and the two nights following, police cars sat within sight of the bus on the street for long periods.

Wanting to avoid another impoundment, the Wilsons kept the bus parked for the whole G-20, though they did participate in some protest marches. (Delyla Wilson is a street medic for activists.)

But the Wilsons say you can tour the bus this Wed., Sept. 30. It will be parked on the main green of the Carnegie Mellon campus from 11 a.m.-5 p.m. Tours are free.