ComedySportz and INDYPROV will team up to present 12 hours of improvisational comedy to benefit 12 local and national charities. In the process, they also hope to set a world record for the longest comedy show. Come prepared to laugh. A lot. The Laff-A-Thon runs from noon to midnight Feb. 28 at Theatre on the Square, 627 Massachusetts Ave. There is a $5 suggested donation per hour. You can make online donations at www.tots.org. For more information, go to www.indyprov.com.