SampleProject.xml

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="default" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <Configuration Condition=" '$(Configuration)'=='' ">Release</Configuration>
        <ProjName Condition=" '$(ProjName)'=='' ">$(MSBuildProjectName)</ProjName>
        <OutDir Condition=" '$(OutDir)'=='' ">$(MSBuildThisFileDirectory)bin\</OutDir>
        <PackDir Condition=" '$(PackDir)'=='' ">$(MSBuildThisFileDirectory)pkg\</PackDir>
        <SourceHome Condition=" '$(SourceHome)'=='' ">$(MSBuildThisFileDirectory)src\</SourceHome>
        <ToolsHome Condition=" '$(ToolsHome)'=='' ">c:\tools\</ToolsHome>
        <PackageVersion>0</PackageVersion>
        <TPath>C:\Program Files\MSBuild\ExtensionPack\4.0\MSBuild.ExtensionPack.tasks</TPath>
    </PropertyGroup>

    <Import Project='$(TPath)' />
    <Import Project='$(ToolsHome)MsBuildTasks\RegexTransformTask.tasks' />

    <UsingTask TaskName="NUnitTeamCity" AssemblyFile="$(teamcity_dotnet_nunitlauncher_msbuild_task)" />

    <Target Name='default' DependsOnTargets='UpdateAssemblyVersion; ReadAssemblyVersion; Clean; RestorePackages; Build; RunTests; Package; Publish' />

    <ItemGroup>
        <Solution Include="$(SourceHome)*.sln">
            <AdditionalProperties>Configuration=$(Configuration)</AdditionalProperties>
        </Solution>
    </ItemGroup>

    <ItemGroup>
        <RegexTransform Include="$(SourceHome)Version.cs">
            <Find>(\[assembly: AssemblyVersion\(")([^/n]*)\.([^/n]*)\.([^/n]*)\.([^/n]*)("\)\])</Find>
            <ReplaceWith>$1$2.$3.$4.$(build_number)$6</ReplaceWith>
        </RegexTransform>
    </ItemGroup>

    <Target Name="UpdateAssemblyVersion">
        <RegexTransform Items="@(RegexTransform)" />
    </Target>

    <Target Name="ReadAssemblyVersion">
        <ReadLinesFromFile File="$(SourceHome)Version.cs">
            <Output TaskParameter="Lines" ItemName="ItemsFromFile"/>
        </ReadLinesFromFile>
        <PropertyGroup>
            <Pattern>\[assembly: AssemblyVersion\("([^/n]*)\.([^/n]*)\.([^/n]*)\.([^/n]*)"\)\]</Pattern>
            <In>@(ItemsFromFile)</In>
            <MatchedExpression>$([System.Text.RegularExpressions.Regex]::Match($(In), $(Pattern)))</MatchedExpression>
            <MatchedExpressionCleanup>$(MatchedExpression.Remove(0, 28))</MatchedExpressionCleanup>
            <Subtract>$([MSBuild]::Subtract($(MatchedExpressionCleanup.Length),3))</Subtract>
            <PackageVersion>$(MatchedExpressionCleanup.Substring(0, $(Subtract)))</PackageVersion>
        </PropertyGroup>
    </Target>

    <Target Name='Clean'>
        <MSBuild Targets='Clean' Projects='@(Solution)' />
    </Target>

    <Target Name='RestorePackages'>
        <Exec Command='"$(ToolsHome)NuGet\NuGet.exe" restore "%(Solution.Identity)" -source "OPTIONAL_NUGET_SERVER_SOURCE"' />
    </Target>

    <Target Name='Build'>
        <MSBuild Targets='Build' Projects='@(Solution)' />
    </Target>

    <Target Name='RunTests'>
        <ItemGroup>
            <TestAssemblies Include="$(SourceHome)\\**\bin\\**\*Tests.dll"/>
            <TestAssemblies Include="$(SourceHome)\\**\bin\\**\*tests.dll"/>
        </ItemGroup>

        <NUnitTeamCity Assemblies='@(TestAssemblies)' NUnitVersion='NUnit-2.6.3' ExcludeCategory='Database' />
    </Target>

    <Target Name='Package'>
        <ItemGroup>
            <MainBinaries Include='$(SourceHome)SampleProject.Host/bin/$(Configuration)/*.*' />
        </ItemGroup>

        <MakeDir Directories='$(OutDir)' />
        <Folder TaskAction='RemoveContent' Path='$(OutDir)' />

        <Copy SourceFiles='@(MainBinaries)' DestinationFolder='$(OutDir)' />

        <MakeDir Directories='$(PackDir)' />
        <Folder TaskAction='RemoveContent' Path='$(PackDir)' />
        <Exec Command='"$(ToolsHome)Octopus\Octo.exe" pack --id="SampleProject.Library" --version="$(PackageVersion)" --basePath="$(OutDir) " --outFolder="$(PackDir) "' />
    </Target>

    <Target Name='Publish'>
        <Exec Command='"$(ToolsHome)NuGet\NuGet.exe" push "$(PackDir)*.nupkg" YOUR_API_HERE -s "YOUR_NUGET_SERVER_ADDY"' />
    </Target>

</Project>