If you’ve ever honked in Dupont Circle because you think Scientology is a cult, well then grab your Guy Fawkes mask. May 24 is your chance to act on the familiar weekend chant (Free Katie Holmes! Free Katie Holmes!). The bobbed wonder, fresh from All My Sons (which Entertainment Weekly hilariously and mistakenly refers to as My Three Sons, which Arthur Miller did not write), will be among the studded cast of the National Memorial Day Concert. Blissfully, she will not be singing. She is instead performing a dramatic reading with Dianne Weist. Also on the bill: Gary Sinese, Joe Mantegna, Colin Powell (doesn’t he live here?), Laurence Fishburne and former American Idol contestant Katharine McPhee. The show will be broadcast live on PBS. After which Katie will shake off her shackles and begin eating again. One piece of advice, Joey: Be wary of the jumbo slice.