Shoot RAW with your IXUS
This is really amazing. There is an alternative firmware available for (some) Canon point and shoot cameras. But instead of having to flash it, you just copy it onto the memory card. It gives you RAW, auto bracketing, bursts and much more. This seems to be especially interesting for underwater photography, but will help whenever you don’t have your full gear with you and you want to do a bit more than just “click”.