I took the day off today, and got a lot done.
Finally got around to investigating the sprinkler system leak. Turns out it wasn't a leak. It was a sprinkler head!
It seems the previous owner built a little wall of stacked bricks on top of an active, functioning sprinkler head. When this type of sprinkler head can't pop up all the way, water just gushes out. Hence the severe pseudo leak.
Silly previous owner.
Also went biking with Mark Leone in Kennedy Grove Regional Park. He's a seasoned biker, so I felt guilty the whole time I struggled slowly up hills. Great workout, though (and the fourth in as many days).
Mark also helped get our ancient gas mower running again. Yay Mark!