According to Wiki, A tax holiday is a temporary reduction or elimination of a tax. Governments usually create tax holidays as incentives for business investment.
Alabama tax free weekend will start this Friday and end at twelve midnight on Sunday August 9, 2009. Alabama will hold its fourth annual sales tax holiday giving shoppers the opportunity to purchase certain school supplies, computers, and clothing free of state sales or use tax. Local sales and use tax may apply – see list of participating cities and counties.