Not having played Super Mario Bros. as a kid, I can't fully appreciate this homemade "dollhouse" (Bowser who?), but maybe your kids will (and you dads).
Cia of DeerDot made this 4-level Super Mario house for her young son and even without understanding the references, I can tell it's awesome. Jenny of Dos Family was visiting them and, thankfully, took pictures of each level for you to check out. Find them at Dos Family.
(Image: Jenny Brandt/Dos Family)