Instructables user Jacco1997 explains how to turn your lace-up shoes into slip-ons by fashioning custom laces made from inner tubes. They look awesome, and the procedure is plenty simple: "Lay out the inner tube and cut it the same length as the shoe lace. Then take that tube and cut two 1 cm. wide strips from it."
Make laced shoes into slip-ons with inner tubes
(via Make)