1.5: Lady Macbeth reads the letter Macbeth has sent her announcing the prophecy of the weird sisters and the greatness they promised to her husband. Lady Macbeth worries that Macbeth would like to have that greatness, but isn't strong enough to do what needs to be done to get it. Upon hearing that the King will stay with them that night, Lady Macbeth appeals to dark spirits "that tend on mortal thoughts" and asks to be the mouthpiece of their deeds. She hopes to be able to speak strongly enough to steel Macbeth to their cause. She hails Macbeth as the future king, and tells him to be strong. She'll take care of the details if he just puts a good face on it.
1.6: Lady Macbeth greets Duncan, his sons and the noblemen, assuring them that she is pleased to take the worries of hosting them the night. She agrees to take them to Macbeth, and catches him resolving himself to not do the deed. She speaks of his manhood as being augmented by their unnatural action of murdering Duncan, and insists that if he just bounds up his courage, she has enough of a plan put together that they can pull off the murder and framing the guards. She convinces him to go through with the deed.
2.2: Lady Macbeth has drugged the guards and claims she is made strong by what weakens the others. She sees Macbeth, who is out of sorts after having done the deed. She is full of reassuring words, and urges him not to think so deeply of what's done, but look to the good that can be gained by it. She urges Macbeth to go wash his hands while she puts Duncan's blood on the sleeping guards. She then takes Macbeth to bed so they don't look suspicious later.
2.3: When alarms are sounded about Duncan's death, Lady Macbeth wakes, seemingly innocent. She mostly plays quiet, but becomes faint when she hears that Macbeth has murdered the guards, which was so not a part of the plan. She is carried from the room.
3.2: Lady Macbeth had earlier been with Macbeth when he was asking for Banquo's whereabouts before the big dinner party. She goes to Macbeth. He seems occupied by his own thoughts, and probes him enough to learn that he's planning something sinister. He claims Banquo's murder is all that stands between them and peace of mind. Lady Macbeth protests, as she is not so comfortable with the idea of murdering Banquo. Macbeth reassures her by saying she doesn't need to know what she doesn't need to know, but that she'll applaud him later for the courage of this act.
3.4: Lady Macbeth plays hostess at the Macbeths' first big dinner party as King and Queen. Her main task over the course of the night becomes stopping Macbeth from looking like a madman while he effectively acts like a madman from seeing Banquo's ghost. She tries to distract their guests, urging them to eat and ignore the King, as he is given to fits of momentary madness, but then she chides him privately for being unmanly. She tells him to chill out and then sends everyone home, as it is clear they are all disturbed by Macbeth's strange behavior. Then Macbeth seems rational again. He is ready to hatch a plan to kill the traitorous Macduff, and promises to visit the weird sisters once more. In private, she does not question his manliness again, nor does she try to reason with him, but tells him he lacks "the season of all natures, sleep." The two go to bed.
5.1: Next time we see Lady Macbeth, she is still sleeping, but seems weary. A doctor and gentlewoman watch her sleepwalking fit, an activity which appears to have been happening a lot lately. She comes out and reenacts bits and pieces of her own plan to murder Duncan with Macbeth, but her sleepy recounting is peppered with her own insecurities, or perhaps guilt. She cannot seem to wash the blood (or its stench) off her hands, and she cries for the wife of the Thane of Fife, perhaps knowing that Macduff, the Thane of Fife, has had his wife recently murdered by Macbeth. She hurries back to bed when she hears a knocking in her dreams, probably remembering the knocking that happened after she and Macbeth saw to Duncan's murder.
Note: One of the Queen's most important impacts occurs offstage. She commits suicide as announced in 5.5, but we do not see her again. She is not even mourned properly by Macbeth, who at this point is driven to further violence by the same desperation that seems to have killed her.