I used to dabble in Google Maps API (application programming interface) quite a bit (but I haven't used it in anger for about 3-4 years). Recently, I was having a look at the Google Maps API v3 and there are a few things I didn't realise you could do with it. I've put together some examples of a customised map background, the cycling layer and adding a KML feed. Pretty useful and very easy to code in JavaScript. I've also given you links to the Google Maps API v3 documenation. Follow the links below to the examples I created:
1 - styled map
2 - cycling layer
3 - KML layer

....I'll add more as time goes on. Let me know what you think.

And here is my first 'proper' experiment with a Google Fusion Table. This map showing showing population density for most countries across Europe (sources Wikipedia and another Fusion Table of Country Boundaries). The Guardian newspaper in the UK love Google Fusion Tables! Check out their data blog for more Google Fusion Tables.