Building multi-line strings, programmatically, in Ruby

Here's something I often do when programming:

code = ''
code << "next line of code #{something}" << "\n"
code << "another line #{some_included_expression}" << "\n"

Is there some better way than having << "\n" or + "\n" on every line? This seems quite inefficient.

I'm interested in Ruby solutions, in particular. I'm thinking something like

code = string.multiline do
  "next line of code #{something}"
  "another line #{some_included_expression}"
end