when the big lottos get real high i'll gamble huge and drop $5 on it. The only other time i gamble and i have a policy on it, is when i find a heads up penny, i go purchase a scratch off with whatever i have in my pocket at the time, max $10 and scratch it with the "lucky" penny i found.
edit- i won't discuss my success ratio as i'm afraid it will give me bad mojo