Did I mention how much I like the folks over at This Week in Relevance? They've just launched a competition where the best OpenHeatMap wins an iPad! I love that idea so much, I'm going to give a free t-shirt to everyone who enters too.
If you're looking for inspiration, just today I've helped people build maps of UEFA cup rankings, amphibian habitats, oil well starts, college alumni, and even someone's friends on Facebook, and that was without the lure of a lovely Apple gadget at the end.
As always, I'll be online as much as I can and available to chat via the awesome SnapABug (I had four simultaneous conversations going at one point this afternoon), or you can email me via email@example.com or IM me at petewarden on Skype.