I found this one to be pretty interesting. It is an interactive map from Collin County, Texas. During early voting right now, voters can vote at any polling location. The GIS team there takes daily voter roster counts and displays a spider diagram for each voting center (when you click on one), showing you where voters are traveling from to each voting center. Statistics like voters by time of day and date are also displayed to the right. You can also change what voting days you want to look at. Pretty cool!