ADHD&D of (a previous) day:
Had this idea before I started this tag, but still want to share it.
With Half-Life being out for 25 years this November, I want to run a short mini-campaign about scientists, technicians, and guards trying to escape from Black Mesa. The Alien RPG seems like the perfect system for such a game as it already has everything you'd need but a few of the monsters.
Being a single adventure by nature, this one I really want to try making happen.