4×17 – Lee Marvin vs. Derek Jeter: Liz Lemon (Tina Fey) starts making an effort to date by attending singles events with Jenna Maroney (Jane Krakowski), and Jack Donaghy (Alec Baldwin) feels forced to choose between childhood love, Nancy Donovan (Julianne Moore), and news anchor Avery Jessup (Elizabeth Banks). Meanwhile, a racist comment sparks an office-wide debate on affirmative action and leaves Toofer (Keith Powell) with a big decision to make regarding his future at TGS. Also starring: Jack McBrayer (Kenneth), Scott Adsit (Pete), Judah Friedlander (Frank), Keith Powell (Toofer), John Lutz (Lutz), Katrina Bowden (Cerie), Kevin Brown (Dotcom), Grizz Chapman (Grizz).
4×18 – Khonani: Liz (Tina Fey) discovers that the TGS staff has been excluding her from their weekly hangouts, and strives to prove that she can be fun. Jack must choose between janitors and the shift time they both want, and Kenneth (Jack McBrayer) aids Tracy Jordan (Tracy Morgan) in being a good husband. Also starring: Jane Krakowski (Jenna), Scott Adsit (Pete), Judah Friedlander (Frank), Keith Powell (Toofer), John Lutz (Lutz), Katrina Bowden (Cerie), Maulik Pancholy (Jonathan).
I grabbed the summaries from Mind Grapes.