As kcies said, Whizzer. It's a small coaster, fairly fast for it's size, and fun. Just when you bring the little kid on it, don't scare him before had (my dad did that to me 10 years ago, and I hated the coaster then. But 12 hours later, I liked it. A lot can happen after you ride the Demon.)
Or if the kid is really brave, have him or her go on the Demon at SFGAm.
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V2, Deja Vu... how can it be better? Add Viper! Oh, wait. It's already there!