This week's New Scientist Invention round-up includes an elastic internal combustion engine (no, really!), a car hi-fi system that adjusts itself to changing accoustics in the auto, and a new twist on collector cards and toys. The bouncy-ball engine sounds nifty as all get-out, but the card thing strikes me as a bit spooky. Several of Olivia's toys regularly "detonate" for no discernible reason already. I can only imagine what they'd be like with something like this.