Hidden among a slew of bugfixes and refinements announced in a posting on the Android project site are a few serious feature upgrades, which could make their way to your G1 fairly soon.
The most practical update may be to the camera functions, which have finally expanded to include video recording. The browser gets a hefty refresh as well, with an inline find function and creatively implemented selective copy and paste, as well as quite a few under-the-hood speed enhancements.
Some of the other updates are a bit more forward-looking, and clearly not focused on the G1. There'll be a framework put in place to allow for simple system-wide on-screen input (read: touch keyboards) and as our tipster pointed out, the mysterious and tantalising inclusion of "Basic x86 support."
Being that this development isn't coming from a hardware manufacturer, x86 support doesn't indicate that a particular new gadget will be adopting the OS, but it does imply that seeing Android on a rich variety of gadgets, including some in unexpected form factors, isn't out of the question. Check the full feature list at the source link. [Android—Thanks, Ben]