Mortal Kombat!
Not because it's a particularly good movie, but because I was a kid when it came out and back then it was the shit. I liked the Street Fighter movie too, but not nearly as much.
This is a funny post because I just recently showed my 8 year old the Mario Bros movie because she's a huge Mario 3 fan. She ended up liking it overall but there were parts that confused her after many hours playing the various titles in the series. She loved Bob-omb though!