Laser Pinball gif
Adam Rifkin stashed this in Lasers!
I make majority of the gifs myself by ripping youtube videos from keepvid.com, and then video conversion software to create the gif, and polish it in GIMP. This program will also do pretty much all of it for you if you want to get started.
I follow around 25 sites for content. Most of the videos are from sites that trend in Russia, China, Spain, and to further obscurity. Like versions of reddit in other countries and languages. Sometimes it's hard to figure out what's been seen there and hasn't been seen here. VK.com is a big one for gifs and videos, it's kind of a combination of fb and reddit.
Great gif making tool: http://www.video-gif-converter.com/