I've fixed the flat on the eldest crinklycub's islabike. Removed the back wheel, got the tyre off without actually pulling a muscle this time, found the hole, patched it, put it all back together, pumped it up, noticed that the bead wasn't sitting quite right in one spot so deflated it, reseated it and re-inflated it, got the wheel back in and sorted the brakes out again. And fitted (more-or-less, judicious application of a couple of cable ties would help) his bike computer that he got for Christmas while I was about it. This is a completely unimaginable level of usefulness for me.
We'll see if it's still got any air in it in the morning!