As Black Friday approaches, Wal-Mart workers and activists are planning another round of protests and strikes at the nation's largest employer on the biggest shopping day of the year. The Black Friday protests come at a time of heightened scrutiny for the company. It made headlines last week when a photo surfaced online of a sign made by workers at one of its stores in Ohio. The sign was taped to a table and read: "Please Donate Food Items Here, so Associates in Need Can Enjoy Thanksgiving Dinner." Wal-Mart says the food drive shows the company tries to help its workers. But critics say it reveals the low wages Wal-Mart pays them. The National Labor Relations Board also ruled last week that Wal-Mart violated the rights of striking workers.