The best one I ever saw was when someone mischievously subjected Rail Link to win the Arc de Triomphe to the small project appraisal formula. Suffice to say, it came out as high risk/ high reward, but was a long way from being the worst spend decision we could have made for £25,000 (about middle ranking IIRC). It amused me anyway that backing a racehorse was considered to be a better use of public money than some of the frankly useless stuff we were being Shanghaied into subsidising (sorry investment funding) each year. At least with Rail Link there was a chance we could get something back, whereas with a lot of these 'pet projects' they were clearly dead money propping up politicians personal playthings (Kids Compnay would be an example of this panning out on a national stage of course).
Suffice to say, investing £25,000 on Rail Link at 16/1 would have wiped out our overspend in one weekend! It transpired to be the best project we could have backed. We did consider writing out to Aiden O'Brien and asking whether he'd be so good as to consider giving the following names to his best 2yo's "Feasibility Study", "Consultants Report", or "IT Training" and see whether we could get that through the audit office