ACTUALLY...... In an interview with Fox News, Paul Ryan tried to explain why his memory failed him. The subject was stimulus funds for a local energy company in 2009 after voting against the Recovery Act. I think he's a little young to blame senility, but here's his statement: "It wasn't my intention to to send letters supporting the stimulus. I didn't know about those letters until very recently when they were brought to my attention."
It just seems rather odd to me that he forgot he signed these letters. But here they are, all hand-signed by Ryan or one of his aides. "Recovery Act" is prominently written in the very first line.