(CNN) Nearly two dozen top progressive groups are joining forces ahead of the midterm elections in an effort to boost Democratic turnout in November and parlay a surge of liberal energy into pre-election activism.

The groups, which include MoveOn, Indivisible, Organizing for Action, Latino Victory, United We Dream and the Working Families Party, among others, will launch a new online organizing hub Tuesday called The Last Weekend, with an aim of amassing more than a million volunteer hours during those crucial pre-election days.

"You hear a lot of that messaging: 'Go vote. We all need to vote.' And yes, we all need to vote. But (Democrats are) in these circles where we're talking to a lot of people that agree with us," said Ethan Todras-Whitehill, the executive director of Swing Left, the group spearheading the effort.

"We need a lot more from those people who are activated," he said.

Organizers from participating groups are also hoping the initiative will help streamline their activities, reducing the number of redundant or confusing appeals to potential volunteers.

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