In 2013, a representative from Florida, Tray Radel, pulled quite the stunt when buying cocaine from an undercover FBI agent. He plead guilty months later to possession of cocaine, and was sentenced to a year of probation. The big hit; he didn't resign. Radel did everything but resigning; keeping his job, he stopped attending sessions of Congress, started a session in rehab to fix his drug problems.
The only good thing about Radel was he donated his salary to charity for the time he was in rehab, but that didn't last long when the Republican Party urged him to resign. Finally, after months upon months of his constituents telling him "you need to focus on your family" and some even saying "you don't belong here", he finally sent John Boehner a letter saying he resigned.
So Radel found out the hard way who not to buy drugs from, then tried to keep his money, it took a year for him to come to his senses and realize he was in the wrong.