To watch the event online, head over to Microsoft’s Windows 10 page at 09:00 (PT), 12:00 (EST), 18:00 (GMT). Microsoft will most likely post up a VOD of the keynote afterwards, allowing anyone on catch-up.
In case you receive the mentioned error while trying to install rmagick then simply issue the following:
# yum install ImageMagick-devel
Once ImageMagick-devel is installed then you can retry installing rmagick using:
# gem install rmagick