After Rainbow Dash stumbled over rock near a river because she tried to land as close to said river without falling in, she going down the stream that takes on the other side of Canterlot mountain. The river takes her to a Big purple fisherman and his frog best friend, who save her. If Rainbow bothered to take her swimming lessons this never would've happened.
The (self-proclaimed) most subdued MLP crossover with the Sonic The Hedgehog games.
The first in a pseudo one-shot series I like to call: Slightly Random Pony and Even More Random Game Character. Or SRPEMRGC or Pony and VGC for short. Where every character will be treated with respect, unless that goes against the characters existence/purpose.
They won't have an overarching plot, each story can be enjoyed on its own. They take place in the same universe though.
1: Rainbow, Big and Froggy
2: Princess Twilight and Dr. Nefarious
3: Applejack and Moneybags
4: Lightning Dust and Polar