From Discover Magazine’s Blog
(http://blogs.discovermagazine.com/cosmicvariance/2009/03/29/international-year-of-astronomy/):

Later this week starts 100 hours of Astronomy
<http://www.100hoursofastronomy.org/>, running April 2–5. The focus is a
worldwide marathon of amateur astronomers watching the sky, culminating
in a star party during the final 24 hours, which coincides with the 3rd
annual International Sidewalk Astronomy night. If you have a telescope
and know how to use it, get out there! And if you don’t, now’s your
chance to find one! Astronomical observatories will be participating via
Around the World in 80 Telescopes
<http://100hoursofastronomy.org/program/75-live-24-hour-research-observatory-webcast>,
which will be a live webcast starting on Mauna Kea (with Gemini, Subaru,
UKIRT, Keck, CFHT, SMA, CSO all participating) and then heading west
until it gets back around to Lick and Palomar 24 hours later.