Yup. There's a famous cheat code for Contra. I *believe* it was for the original NES version. Well the guy's over at Digg.com hid the code in their comments system so that if you enter it in, it will show all the nested comments in a full expanded tree. I'm pretty sure the code is:
up, up, down, down, left, right, left, right, a, b, a, b, start
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