Here's a sign — albeit a small one — that the drought may soon be over: Valve has filed for a European trademark on Half-Life 3. That's it in the screencap above. For more, run a search on the European Union's database.
There have been false starts before, of course. As far back as 1999, Valve snapped up the domain half-life3.com. It's been dormant ever since, redirecting people to a promotional page for the Orange Box, which itself debuted in 2007. But at the very least, this latest development gives fans a little more cause for hope.