Stuck clutch pedal

best bet, air got trapped in the system and somehow it magically popped out on its own. I would recommend changing the fluid if its dark. After that check the level every now and then to see if sits on the same spot all the time.

The fluids look fine. After driving it for another week it happened again. Clutch pedal starts to go slack and then sort of just slides in toward the floor on its own. This time, I pulled it back out and voila, it works again. The air explanation is interesting, I seem to have a small vacuum leak somewhere as the car idles high now and then. Could this have something to do with it? Or should I just change out the master and slave and hope that fixes it.

if you have the NA stock master cylinder you don't have a clutch booster, so you can disregard that.

Before you go ahead and change both, I'd say replace the fluid. With time it will condense some water and affect its properties.

If after you replace it the problem persists, then go ahead and replace both and you'll be golden.

Went ahead and replaced both, problem solved.