I do a couple of non typical things in the microwave.
I use it for blanching vegetables such as green beans in the pricked packet they are sold in and then rinse with hot water afterwards.
I use the microwave to make creme caramel because life is too short for cooking anything au bain marie. I zap 10 minutes on half power, then turn down to the lowest setting and zap at 10 minute intervals until the middle is firm. This takes usually three zaps so takes less cooking time than au bain marie in the oven too. Similarly I use the microwave for recipes calling for melted chocolate.
I make a pretty good facsimile for oil free potato chips by thinly slicing potatoes in the food processor, then laying in a single layer on a large plate lined with silicon mesh or silicon baking paper. Season and zap for 6 minutes on high. Remove any that are golden brown. Zap stragglers at 1 minutes intervals being careful because the margin between golden brown and burnt is quite narrow. These harden to a crisp when cool.
Any other tips for kitchen hacks on less conventional things to do with the microwave?