You know those suitcases that are handcuffed to wrists in the movies? This is kind of an updated version of that for laptops.
The "Laptop Wallet" from Vienna-based Working Class Heroes (we don't often get to cite an Austrian company) is a slip cover with an invaluable feature for those of us who suffer the occasional lapse in basic motor skills--a leather wrist strap. As Gadget Grid notes, it's ideal for butterfingered students who might otherwise jeopardize their parental relationships by dropping their brand-new MacBook.
It's not a bad idea for some coordination-challenged adults as well, though we're not naming any names.