Thursday was a rare day in the history of Minneapolis elections: voters could cast as many ballots as they wanted.

In fact, city elections officials were encouraging ballot-box-stuffing on the first day of mock voting, meant to familiarize voters with some new machinery and with a "ranked choice" ballot.

"We want to make sure our voters in this election -- and every election -- are comfortable and informed," said assistant city clerk Grace Wachlarowicz, who was helping preside over the impromtu polling place in the City Hall rotunda Thursday.

The Nov. 5 city election will be the second -- the first was 2009 -- in which voters can select several candidates for each office based on their preference, rather than voting for just one.

This year, voters will encounter new machines, which will gobble up ballots much like the old ones but will then display on a computer screen whether the ballot was fully acceptable or whether it contained any mistakes -- lack of a first preference for an office, for example, or voting for the same candidate as a first, second and third preference. In such cases, the computer will ask voters if they want to cast a new ballot, or let the machine toss out the mistake but accept all other votes.

Wachlarowicz added that the new machines will keep a running tally of votes, so a hand count won't be required after the polls close. That should make results available immediately.

"It's a huge advancement," she said.

Only 11 voters turned out Thursday, But others who want to sharpen up their skills will have more opportunities. The city hall polling place will be open every weekday from 11 a.m. to 1 p.m. through Sept. 16, and others at four Minneapolis high schools next week. The schedule: Monday, Roosevelt High School, 4029 28th Av. S.; Tuesday, Henry High School, 4320 Newton Av. N.; Wednesday, Washburn High School, 201 W. 49th St.; and Thursday, Edison High School, 700 22nd Av. NE.The mock polls in the schools will be open from 3:30 p.m. to 7:30 p.m.

Voters Thursday ranked their favorite parks. On Nov. 5, voters will choose a new mayor, 13 city council members, two members of the Board of Estimate and Taxation, and all nine Park and Recreation Board members. They'll also be asked two questions about whether they want plain language in the city charter.

Absentee voting will begin Sept. 20.

And as with any election, officials are eager to find people to work as judges in the polling places on Election Day. About 2,000 are needed, either as volunteers or to work for $8.75 per hour, said Jilla Nadimi, Minneapolis election judge co-ordinator. Employers sometimes make allowances for people who work as election judges.

Anyone interested in volunteering should call Nadimi at 612-673-3870. Other information on voting, including registering to vote or volunteering to work as an election judge, is available at http://vote.minneapolismn.gov/