SIGGRAPH’s early registration deadline is June 4th, after that the price goes up $175 or so, depending. News of which made me look around for graphics conference calendars. I didn’t find much – if anyone knows of others, please do let me know.
The Upcoming Graphics Conferences page on wikidot lists most of the graphics conferences I know about, and tons I don’t. It doesn’t list HPG 2010, however. I wrote the website maintainer about this omission but it’s a week later and no response or update.
A handy schedule of computer graphics conferences is available from a student at the Max Planck Institute. This one’s handy for researchers, as it gives submission dates. Oddly, HPG 2010 is again missing.