Okay you can use it wherever you would use an orange, more or less. As Miniman said, there is marmalade or a jelly but you can also use it as a glaze as per duc a l'orange or on a ham. Mandarin and orange segments are often used in salads. You could try bottling them in brandy in a similar way to cumquats. You can use the juice and rind to make cakes and desserts or put them thru a crepe suzette. Coat the segments in melted chocolate for an after dinner treat. Squeeze them and make a sorbet or an icecream. Tangelo butters. Stuff a chicken with them instead of a lemon. Use them with cranberries to make a relish akin to the recipe recently shown on DC that used orange with the cranberries. Try your hand at making a liquour. Make dried peel for your next fruit cake.
They keep a fair while - or they should - so you could just eat them.
Too many restaurants, not enough time...