The event will be hosted by Google mobile product management director Hugo Barra.

The invite said that Google will be unveiling a couple of cool new mobile features. Barria comes to Google from Nuance communications, a speech recognition powerhouse, but Google phones already recognize speech. The last event of this sort yielded Turn-by-turn directions in Google Maps (which is awesome).
Another area of intrigue is video calling which Fring has been doing on Android since before Apple debuted Facetime. But a built-in Google (GOOG) solution would be an instant success.
Barra seems to be excited about OCR Translation and Google Goggles and Google Latitude type products in his twitter feed so those are always possibilities.
Also, Google Music is due for an unveiling.
There are also a slew of new Android phones released this week including the Dell Streak, Sony Xperia X10, the Droid 2 running Froyo and some Samsung Epic 4Gs should be rolling off the assembly line as well.
Tune in Thursday to find out!