One of the more recent acquisitions, from Anime Chaos. You just know that something terrible just happened to Ranma, from the expressions on Ukyo and Genma's faces... as usual, Akane is just annoyed!

In actuality, I just found this cel about ten minutes in to the episode "Showdown! Can Ranma Make a Comeback?" Its the 5th episode in the 4th season. Akane has just booted Happosai into the stratosphere for picking on Ranma after taking away all his strength... ("He makes me so mad, sometimes!")