John Mayer, Jimmy Kimmel and Jeff Ross served as hosts for their late friend on Wednesday at an annual fundraiser for the Scleroderma Research Foundation, with the event raising $1.2 million for critical research. Bob hosted SRF’s signature event, “Cool Comedy • Hot Cuisine,” for 30 years before his death … and this year’s fundraiser included a special video tribute to Bob, presented by John Stamos and Mike Binder. Dave Chappelle appeared at the Beverly Hilton for a surprise performance, even sharing a personal video message he got from Bob before he died. Bill Burr joined Dave on stage for some jokes as well. Other celebrity performers included comedy cameos from Howie Mandel and Kevin Nealon, as well as a musical number from Mayer. Joel McHale led the live auction. Attendees plunked down $500 just to get inside the building … and had a sit-down dinner curated by celebrity chef Susan Feniger. Bob’s sister Gay died of scleroderma — a group of rare diseases involving hardening of the skin and connective tissue — in 1994 when she was just 47 … and SRF’s annual fundraiser has now raised more than 28 million dollars for research to find a cure.