Use next:
(1..10).each do |a|
next if a.even?
puts a
end
prints:
1
3
5
7
9
For additional coolness check out also redo and retry.
Works also for friends like times, upto, downto, each_with_index, select, map and other iterators (and more generally blocks).
For more info see http://ruby-doc.org/docs/ProgrammingRuby/html/tut_expressions.html#UL.