A few years ago we were Fred and Wilma! This was done with some thrift store tees and double sided iron on interfacing.
Before that I was a storm trooper. Same stye of costume making. Just ironing on black cut outs from a t-shirt onto a white t-shirt.
I loved sewing my Phoenix/Jean Grey costumes but making Bane's mask for my husband was WAY too much fun. I used kids' foam craft clay and painted it. I ended up selling both of these costumes on ETSY later.
The most most most fun costume ever was being an AVATAR.