An Aspen judge ordered Charlie Sheen to spend a month in rehab after the actor pleaded guilty to misdemeanor assault in his domestic-violence case. Two other charges were dropped. Sheen must also serve three months of probation and undergo 36 hours of counseling on domestic violence. The star of Two and a Half Men cheerily entered his plea; when the judge asked why he was doing so, Sheen said, “Because I’m guilty.” Earlier, Sheen pleaded not guilty to felony menacing and two other misdemeanors when his wife, Brooke Mueller, said he held her down and threatened her with a knife. Mueller entered rehab for substance abuse a month later. Sheen’s lawyer says the couple hopes they can repair their relationship.