So, I haven't done the US Mint hack, yet....<p>But, I have spent the last 3 months buying the longest, cheapest round trip fares that I've been able to find, also called "mileage runs". American Airlines has had a "Double Elite Qualifying Mile" promotion, which means that I can reach Executive Platinum with American while flying only 50,000 miles instead of the usual 100k miles. This fall, I've done weekend trips to Madrid, Frankfurt, Florida, visited family in the Mid-West, and this upcoming weekend, a I'm finishing with a round trip to Barcelona. I'm flying out from San Francisco on Friday morning, spending 2 days in Barcelona and I'll be back home by Monday.<p>All told, I've spent $2200 on flights, and a bit more for hotels + food. What I get in return is being able to upgrade to first class for free on any domestic flight on American, 8 upgrades on international flights (worth $300-400 each if I sell them), and enough earned miles to buy two tickets worth $1100 to visit family in Central America this spring.<p>I have a hunch, though that after flying first class all next year on American, I'm going to have a really hard time flying coach again. I'm afraid this might be a bit addictive.<p>A friend of mine, (mcargian on hn) hosts a podcast about this stuff at <a href="http://upgrd.com" rel="nofollow">http://upgrd.com</a>. He turned me on to it.