Good luck on the 10k, the 24h sounds like fun. I need to get some of my buddies to do some more of these event things. 4 laps is 24m, 40k plenty of distance for a day's work.
As for my races. I've got a 10k coming up, but not planning on putting in 100% into it, as I'm working on a 1/2 training plan this summer/fall, for BayState half marathon. I've run the full 3x, this is my first time doing the half. It's in mid October, and I've got a bail out half scheduled for Nov 12, which I may skip, if I run my target time for the 1/2 this fall. There is really nothing hanging on the race, other than trying to PR, and get sub 1:30. I ran a 1:31:xx this spring, and I've dropped some weight, and had a good training cycle, so I'm feeling positive about it.