It's genius! The activist groups are using marijuana as a way to get people to vote! (Probably not true, but it's a side-effect.)
Many people in Colorado and Washington who are vehemently against legalizing recreational marijuana use are about to put forth a referendum (if they haven't already) to re-criminalize it. Because of the controversy, many people will go to vote to re-criminalize it and, if the opponents of this are wise, they will go to vote to keep it legal.
In the process, they will be bombarded with other issues at the ballot, including elections. Most of them will probably then vote on those as well.
I understand that this probably happens with many other issues, but marijuana legalization looks to be the most impacting current issue that could have this effect.