Here's a new development update from Croteam, developers of the Serious Sam franchise:
Since the Serious Sam 2 was released in end of 2005, we have been working hard on a number of things, one of which is new next-gen 'Serious Engine 3' technology. More on this will come in future updates.
We have also recently started the development on two games, one of which is the next Serious Sam FPS game. Here, we are pretty close in signing the publishing deal, so when that happens, you'll hear it here as well.