Worksheets are not just daily activities teachers use to help drive the day's lessons home to students. They can also be used as the basis of projects. For example, ABCteach.com has a worksheet that helps students create a voting booth. This worksheet explains how to use a cardboard box to create a booth; to do so, you just need to cut two adjacent sides off of a cardboard box, so that the box can be placed on top of a desk to conceal your vote. You can then use this voting booth to teach students about who can vote. Once the booth is built, assign all the students in the class a fictional age, and only let the 18+ students enter and vote. Once this is over, the students may discuss whether the system is fair.
The laws regarding who can vote are often controversial. For example, many people feel that felons should be allowed to vote, because it's always possible that a felon has been falsely convicted. One project you can do on this topic with sixth graders is a kind of simulation. Set up a classroom dynamic for one week where the class votes on what kind of homework assignment they have, and any student who breaks a school rule is no longer allowed to vote. When the week is over, poll the students on whether they thought that system was fair, then explain to them how this system compares to the electoral system.
Over the years, the right to vote has been extended to various elements of society. Today, only noncitizens, children and felons cannot vote. In the past, however, women, minorities and people who didn't own property could not vote. Sixth graders, who are young and (sometimes) naive, may have a hard time coming to terms with this fact. To drive this history home to them, assign a project where the students have to depict the history of voting rights. Students can choose between time lines (a line of key dates in the history of voting rights), collages (collections of images from presuffrage times), and presentations (getting up in front of the class to give a speech on the history of voting rights).
The right to vote varies significantly around the world. For example, in some countries, members of the military are not allowed to vote. Sixth-grade students are just beginning to learn about geopolitics and political differences around the world. Doing a project that involves comparing voting rights around the world can help students understand differences in political systems. For example, you can assign a project where students need to make a poster comparing two countries in terms of voting rights. In this project, the students put two countries on opposite sides of the poster, then compare voting rights in either country according to various attributes (voting age, religious minority rights, military voting or voluntary vs. compulsory voting).