Well today my battery cooked itself... I was out and about and went to start the car and it kicked over for a fraction of a second and then nothing, everything went dead.
Low water levels in the battery was what I found.
When I topped up the water one of the cells started to boil.

Disconnected the battery and it stopped.
$105 down and a new battery later and all is well again.
Moral of the story: With the days getting hotter check the water levels in your battery more often.