I'm sure most of you have seen this but VGCats put out a humorous video dealing with the ending song played in Portal, it's addicting as all hell but the video has some funny parts.
Youtube Link: http://youtube.com/watch?v=NAnfG3KfPB0
Which coincidently the top limerick from limerickdb.com is this:
#286 + (1373) - [X]
There once was a buggy AI
Who decided her subject should die.
When the plot was uncovered,
The subjected discovered
That sadly the cake was a lie.
I love that end song.