Ok I'm sure you were hoping I was going to announce something cool like the hidden flight simulator in excel. 
Sorry, here is some XAML instead.
Windowless Easter Egg
<Window x:Class="WindowlessForms.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="400" Width="600" WindowStyle="None"
AllowsTransparency="True" Background="Transparent" WindowStartupLocation="CenterScreen">
<Border>
<Ellipse Stroke="Black">
<Ellipse.Fill>
<RadialGradientBrush GradientOrigin="0,0.4" Center="0,0.5" RadiusX="1" RadiusY="2">
<RadialGradientBrush.GradientStops>
<GradientStop Color="AliceBlue" Offset="0"/>
<GradientStop Color="Blue" Offset="0.1" />
<GradientStop Color="AliceBlue" Offset="0.2" />
<GradientStop Color="blue" Offset="0.3" />
<GradientStop Color="AliceBlue" Offset="0.4" />
<GradientStop Color="Blue" Offset="0.5" />
<GradientStop Color="AliceBlue" Offset="0.6" />
<GradientStop Color="blue" Offset="0.7" />
<GradientStop Color="AliceBlue" Offset="0.8" />
<GradientStop Color="blue" Offset="0.9" />
<GradientStop Color="AliceBlue" Offset="1" />
</RadialGradientBrush.GradientStops>
</RadialGradientBrush>
</Ellipse.Fill>
</Ellipse>
</Border>
</Window>