BREAKING: Japanese astronomer Masayuki Tachikawa may have spotted yet another impact on Jupiter! Here's the video: Emily Lakdawalla at The Planetary Society blog has the details.
[UPDATE: Sky and Telescope has more info too.]
The video looks legit, but to be absolutely sure we'll need to get either more video from a different location, or a telescope that might be able to spot any impact scar left from this. [Update 2: That Sky and Telescope link has also been updated; a second astronomer recorded the flash! It's real; Jupiter got hit again!] As Emily points out, there may be a lot more of these than we imagined, and it took constant vigilance of amateur astronomers to find them. If so: very, very cool.