Golden State Star Party (GSSP) is a 4 night dark sky event held each summer usually in early July at Frosty Acres Ranch in North-Eastern California, near Mount Lassen, alongside rural Adin, California. GSSP has dark skies from horizon to horizon, and room for 100s of astronomers.
Go to http://www.goldenstatestarparty.org/ for more details.
2014 dates are Wednesday June 25th through Sunday June 29th.