Here you buy tickets for Universal after 5pm. For Mardi Gras, at least that is how we understand it, but again we have annual passes so we get in free anyway. You can get the annual pass on a payment plan. We pay 32 a month for two of them. The after 5 pass is how Unviersal explained it to us.
http://www.universalorlando.com/mardigras/tickets.html#mardigras

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Andrea