With Google CEO Eric Schmidt as emcee, several Google execs showed off a variety of cool technologies, based on the upcoming fifth version of HTML that will make browsers more powerful than ever as application platforms. These include new markup tags such as <canvas> and <video> that will provide native support for, respectively, 2D drawing and running videos in browser–tasks which today typically involve installing plug-ins such as Flash or Shockwave. As guest speaker Jay Sullivan, a vice president at Mozilla, put it, HTML 5 will get “things like video out of plug-in prison.”

Also coming: new APIs for other features such as offline storage of data (so that you can use Web apps even when you’re not online), 3D graphics (think first-person-shooter in a browser) and geolocation (Google demo’d a new “My Location” button on Google Maps that you can opt to share with others — hmm, will this supercede Zhiing?).

An Android guy (Romain Guy, to be precise) talked about how the next version (code named Donut) will include a neat open-source text-to-speech engine and multiple language packs. Used with a translation app, this could basically turn your phone into a neat portable translator for supported languages.

You can read Google’s official Google I/O keynote press release to see what they thought was important (but remember, it’s for developers).

As for news you can use right now, head on over to Google’s Web Elements page, which has an assortment of neat code snippets that make it super easy to instantly add modules for Google search, chat, YouTube video, maps and more to your Web site.

You can add this Google Custom Search web element by pasting a few lines of code onto your site.

The best part of the keynote, though, was the end, when Google Engineering VP Vic Gundotra announced that all attendees would be receiving free Android phones – and SIM cards for 30 free days of unlimited voice and data use. I’m looking forward to some quality time with Android.