Louis C.K. hosted last night's SNL and the most memorable sketch was definitely this Seth Myers written parody of C.K. spoofing his own show, Louie, in character as Abraham Lincoln.
There's no doubt that this was inspired by the classic Joe Piscopo sketch where he played an annoying Abraham Lincoln in Ford's Theatre (here's a transcript of it to jog your memory, no video of it is online).
Also, see @FakeLouieEps for more Louie related parody.