I have been to this several times - great art and music and interesting people.

Playa del Fuego is Burning Man festival in Delaware - a celebration of
the spirit of radical self-expression, community, and participation. And
plenty of music and fire art! Playa del Fuego is the burning event of
the Mid-Atlantic Region. The Spring 2010 event will take place this
May Memorial Day weekend,(5/27/10-5/31/10) from Thursday 5 pm through
Monday noon. Tickets are $50 for 4 days (what a deal!) for camping. The
cut off for online tickets is Saturday March 27 (first tier), Tuesday April 27, (second tier) . FYI Tickets often sell out with in 10 minutes of the posting time.

More info at
http://www.playadelfuego.org/