Gif Central boasts hundreds of funny animated gifs. Only the best of the best make it onto this site, with most of them having an accompanying source. No tumblr-esque one-second-long disappointments. No obscure titles or descriptions.
That's really funny stuff. I'm laughing my ass off.
This is an animated reaction gif of a man with a deadpan facial expression saying "That's really funny stuff. I'm laughing my ass off." This is from the 2008 movie Marley & Me. Use this whenever somebody says something that is unfunny.