International Marconi Day event is April 28

From the ARRL - Amateur Radio Relay League...
Special event stations will be on the air Saturday, April 28 (UTC), to mark International Marconi Day (IMD), a 24-hour Amateur Radio event comemorating the birth of wireless pioneer Guglielmo Marconi on April 25, 1874.
Participants can qualify for awards by making contacts on 160 through 10 meters (CW, SSB and digital) with designated IMD stations operating on or near a site where Marconi carried out experiments -- or where Marconi equipment was used prior to his death in 1937.
The sponsoring Cornish Radio Amateur Club (CRAC) will operate GB4IMD from Pendennis Castle, Falmouth, Cornwall, overlooking Falmouth Harbour where Marconi spent some 10 days aboard his yacht Elettra in April 1923. Additional IMD stations will be on the air from the UK, the US, Canada, South America, Australia and Europe. The IMD Web site has a list of IMD 2007 award stations. If you would like to operate an IMD 2007 award station, register your station prior to the event, providing full details.