First, take a pyrex glass measuring glass and melt your butter in the microwave. Use 30 second increments and stir in between. Once the butter is melted, stir the brown sugar into the cup. Pour into the bottom of the crockpot. Place the Maraschino cherries on the bottom of the crockpot. Be sure to spread them out so there are some all over the bottom of the crockpot. Pour the pineapple tidbit, along with the juice, in to the crockpot. Spread the pineapple tidbits out so it's one layer across the bottom of the crockpot. Next, pour the cake mix in and spread it evenly over the top of the pineapple but be sure to cover all the fruit. Pour the melted butter evenly on top of the cake mix. Place the cover on and cook on high for 2 hours. To avoid any burn marks, turn the crockpot halfway through the cooktime. Once your bake time is finished, remove the cover and let cool for a half hour. Scoop some of the cake onto a plate with a generous amount of vanilla ice cream and enjoy!