Recently I was trying to use StringBuilder.AppendFormat to build some javascript, and was hit with an exception when trying to do this:
sb.AppendFormat("function {0}(args) { return false; }", someVariable);
The problem is that you can't have { or } inside an input string for string.Format(). The solution is actually fairly straightforward:
sb.AppendFormat("function {0}(args) {{ return false; }}", someVariable);
Instead of using "\" as an escape character, you would use { or } (depending on what you want to escape).