Today is your last chance to sign up for Google Code Jam. The company setting up this contest, Topcoder, holds plenty of these contests, but since I haven't heard of them before now you can tell the effect on their business of the Google name. Clearly Google's technical street cred is hard to beat, so a Google branded test of your skills is just what you need to motivate yourself.

UPDATE
My goodness, one forgets easily. The C++ part of my brain has atrophied. The C# part has not yet been built. The VB.Net part I cut out my self using a teaspoon, and the Java part is this bulbuous appendage to the back of my head doing very little and generally being in the way when it does so. Must study or fail miserably...