During my last game at the local chess club, I played somebody who spend enormous amounts of time away from the board, even on his turn.
So I had a lot of time to consider each position in great depth, After two moves such a situation occurred.
1.d4 Nc6 2.c4 e5.
I had the black pieces
In this position I had some 20 minutes to consider what his moves would be, he usually is a big fan of trading so I thought he might play 3.dxe5, after which I am still fairly sure that 3.-Nxe5 4.e3 is the best continuation to not give black an edge.
However the continuation I found to be so funny and why I thought this would be a great post is.
3.dxe5 Nxe5 4.b3 Qf6 5.Bb2 Nd3+ 6.Qxd3 Qxb2 7.Qc3
which gives this position
Here black has a really cool move, try if you can find it, after you can scroll down to see the answer.
7.-Bb4!! 8.Qxb4 Qc1#
Here is a animated version.