I was on Zazzle today and they were showcasing a funny mom mug. I decided to take a look at Zazzle's offer under that category. I didn't find any big surprises ("Best Mom Ever" / "I'm a mom. What your superpower?" and so on), but I think even these old messages can be okay in a good way when presented as a gift. I mean, I bet any mom would love yet another "Best Mom Ever" mug over boring plain solid-color (or white) mugs. Also, remember that you can personalize these custom mugs further by adding a photo, your name, the name of your mother, etc.
So here's a selection of fun or downright funny mugs for mothers of all ages.