Hey Space Placers!
The Moon and Earth get smacked every day by incoming cosmic debris in the form of comet and asteroid dust and small space rocks. On Earth we had the Chelyabinsk impact on February 15, 2013 and nightly fireballs (bright meteors) to remind us of this.
As to impacts on the Moon NASA has gathered video of over 300 impacts on the near side from observers using telescopes. NASA has become a clearing house for this data from its own telescopes and other observers, including amateur astronomers. NASA obtains new impact candidate videos all the time for analysis and confirmation.
NASA had reported last year on the largest observed lunar impact to date but a new "biggest boom on the Moon" was reported today by Spanish astronomers. The impact took place last September 11, 2013 (a most ironic date) and was bright enough for anyone looking at the Moon to have seen it. The reporting team estimates the flash from the impact would have been as bright as Polaris, the North Pole star.
I suspect that there will be new "Biggest Boom on the Moon" record holders as the nights and years go by.
I hope I am luck enough to see one for myself.
Sky Guy in Cold Again VA