Packed with fascinating facts and big laughs, this spoof edition of Dragons' Den travels through time as great (and not so great) inventors from history pitch their ingenious ideas. Evan Davis is joined by four Dragons with more than a passing resemblance to Duncan Bannatyne, Hilary Devey, Theo Paphitis and Deborah Meaden. But will they cough up for the creators of WiFi, the whoopee cushion, the toothbrush and the erratic genius of Leonardo Da Vinci?