June 11 Take the Reach the Peak Challenge as part of National Get Outdoors Day.
July 16 & 17 Explore the park through film at the Summer Film Festival with short and full-length films ranging in topic from volcanoes to astronomy.
July 30 Join Lassen Park for an official dedication of the rehabilitated Lassen Peak Trail featuring a special presentation followed by a ranger talk on the summit.
August 6 Celebrate Lassen Volcanic’s 100th birthday at a celebration featuring family activities, displays, music, barbeque, ranger led programs and raffle.
August 12-14 Join park rangers at the Dark Sky Festival where NASA scientists, astronomers, and astrobiologists celebrate all that is out of this world. Enjoy special programs, presentations, hikes and junior ranger activities both day and night.
September 17 Celebrate 100 years of Lassen with local art, wine and music. Park admission free in celebration of Public Land Days.
All this and more at https://www.nps.gov/lavo/planyourvisit/special-events.htm