What does map(&:name) do in this Ruby code?
events.map(&:name)
is exactly equivalent to
events.map{|x| x.name}
it is just convenient syntactic sugar.
For more details, check out the Symbol#to_proc method here. Here, :name is being coerced to a proc.
By the way, this comes up often here - it's just very hard to google or otherwise search for 'the colon thing with an ampersand' :).