McGonagall takes a stroll about the castle in cat form. A deleted scene from OotP.
Only the students studying for their O.W.L.S and N.E.W.T.S were around for the holiday, making for a quiet castle around her. The past few weeks had been hellish after Dumbledore's stunt with Umbridge that had put her in the position of looking out for Hogwarts. You old fool, Albus, she thought as she continued down the corridor. Taking on her cat form helped to calm her down, gave her a bit of much-needed peace from the demands around her.
It was a warm enough morning, so she decided to take a stroll around the grounds before returning to her office and schedules and career advice notes. She passed by the greenhouses and saw Neville working diligently in the soil, muttering to himself and referring to a book open at his side. His toad, Trevor, hopped about, and she had to repress the urge to bat it about a bit. She was much too old for kittenish urges, she thought as she padded away. She did hope that Neville did well on his exams; she would have to mention his grandmother's own scores to him soon.
She wandered into the Great Hall, some gawdy animated Easter eggs and bunnies catching her eye. Dumbledore must have charmed them to appear in his absence; she wouldn't put it past him to have charmed decorations to appear for every holiday permanently while he was gone. She sat, lost in thought and staring at the little pastel bunnies frolicking for a while. She was brought out of her thoughts by a noisy group of fifth-years walking by, talking animatedly and carrying their books outside to study. She saw the familiar red hair that signaled a Weasley, along with that annoying twit, Lavender, among the group. It was hard not to notice the angst and romances of students; indeed, it made great fodder for gossip among the professors, she thought with a mental grin.
As she padded up the staircase back to her office, she saw a pale shock of blond hair in the distance. As she drew closer, she noticed Luna examining the crevices of the stone walls of the school. She shook her head and kept walking. She had a soft spot for the girl, even if she was an odd one. If she ever got past her beliefs in Blibbering Humbingers and Wrackspurts, she'd make a fine and successful Wizard someday. Of course, she thought wryly, somehow she wouldn't put it past Luna to actually find proof of one of her creatures, showing them all up.
As she turned into the corridor where her office was, she saw Mrs. Norris streak by, Peeves in hot pursuit. Moments later, Filch ran past, wheezing and gasping for breath, and yelling for help. She started to change back, then thought better of it. Let that nasty Umbridge woman deal with it - after all, wasn't she calling herself Headmaster these days? She walked into her office and hopped up on the padded chair by the sunny window, determined to take a short cat nap before returning to the real world.