Minnesota's elderly population will double in the next two decades, so that by 2030 nearly one in four residents will be over age 65. The Twilight Zone is an occasional series by Star Tribune reporters examining the way this demographic wave will change neighborhoods, health care, schools and state priorities.

July 18: For a glimpse of our graying future, look no farther than Roseville.

Aug. 2: Helping seniors stay at home.

Aug. 22: Aging boomers will strain caregivers and state budgets.

Sept. 21: End of an era for young suburbs.

Oct. 5: Who will support public schools?

Today: Condos, co-ops and "granny pods."