gistfile1.txt

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
 <Import Project="$(MSBuildProjectDirectory)\MSBuild.Community.tasks" />
 
 <Target Name="Test">  

   <Message Text="Test build"/>

   <ItemGroup>
     <Frequencies Include="262;294;330;349;392;440;494;523"/>
     <!--<Frequencies>262;294;330;349;392;440;494;523</Frequencies>-->
   </ItemGroup>  

   <Message Text="%(Frequencies.Identity)"/>
   <Beep Duration="300" Frequency="%(Frequencies.Identity)"/>

   <Error Text="TestError"/>

   <OnError ExecuteTargets="OnError"/>
 </Target>

 <Target Name="OnError">
    <Beep Duration="740" Frequency="262"/> 
    <Beep Duration="530" Frequency="262"/> 
    <Beep Duration="140" Frequency="262"/> 
    <Beep Duration="740" Frequency="262"/>
    <Beep Duration="530" Frequency="311"/>
    <Beep Duration="140" Frequency="294"/>
    <Beep Duration="530" Frequency="294"/>
    <Beep Duration="140" Frequency="262"/>
    <Beep Duration="530" Frequency="262"/>
    <Beep Duration="140" Frequency="247"/>
    <Beep Duration="740" Frequency="262"/>
 </Target>


</Project>