If Jabba the Hutt were a man, you'd see him at the beginning of this video. He wasn't a human man, but you see him at the beginning of this video anyway. Before the final design of the character was realized, George Lucas shot his first Jabba scene in the original Star Wars with an actor! The footage was later overlaid with a stop-motion creature. We also get to see some of the rejected Jabba the Hutt designs, before he eventually became a giant slug.
By the time Return of the Jedi came around, Jabba was ready for a bigger share of the plot. He was constructed as a puppet operated by multiple technicians, who explain here what their duties were. One puppeteer's sole task was to smoke a cigar and blow the smoke out of Jabba's pipe! All this work, and the character ended up being replaced by CGI in the Special Editions. -via Laughing Squid