Inspired by Florian Gross's Execute as Ruby Code Service for OS X
(http://www.ruby-forum.com/topic/102680), I have created InstantERB. It
uses the incredibly useful AutoHotKey utility. It will run any selected
text through ERB.
For example, selecting the following block of text and hitting <Windows>+I:
The value of pi is approximately <%= Math:I %>.
% 3.times do |i|
<%= i %>
The value of pi is approximately 3.14159265358979.