Following Ted's example, I'm back at the track with an eye to getting faster, or at least not getting slower as I approach 40. (In triathlon years I am already 40, but in real life I have a few months to go.) Today was 3 x 1 mile plus 1 x 800m (I couldn't stomach the 4th mile!) at the so-called "tempo pace" -- which is in theory my per-mile pace running a 10K flat out -- with 1 minute rest in between.
This gives the lie to the idea that marathoners are crazy. To my lights it's the short stuff that is really unpleasant!