Spoiler alert! Today is the 25th anniversary of Half-Life, Valve's original
first-person shooter. We'll call this the game's lead-210 anniversary, since its
half-life is 22.3 years according to
Wikipedia and that's as close as we can find to an isotope with a 25-year
half-life. The celebration of the occasion is fully underway, including
announcement that the game has received a big update, and is currently
free-to-keep on Steam.
So get moving! They're waiting for you Gordon. In the test... chamber.