If you've ever stumbled across a great piece of code that you wanted to integrate into your web app, but found it in the language that your NOT currently coding in,
there's an easy way to use it without having to rewrite the code in your current application's language.
In the web application file directory, create an additional folder for the other language. See in the image below that I have a folder for C# files and another for
VB.NET files.

Then, in your web.config modify the <compilers> section so that it shows both of these elements. You should only have one of these initially reflecting the language you're coding in.
<system.codedom>
<compilers>
<compiler language="vb;vbs;visualbasic;vbscript" type="Microsoft.VisualBasic.VBCodeProvider,
System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" extension=".vb" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="OptionInfer" value="true"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
<compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider,System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="4">
<providerOption name="CompilerVersion" value="v3.5"/>
<providerOption name="WarnAsError" value="false"/>
</compiler>
</compilers>
</system.codedom>
Then, under the <compilation> section add a directoryName for the App_Code folders you created. One for each language type.
<compilation debug="true" strict="false">
....
<codeSubDirectories>
<add directoryName="myVBCode"/>
<add directoryName="myCSCode"/>
</codeSubDirectories>
....
</compilation>
And that's it. Compile, browse and your done. Voila!
Very easy, huh?