Model railroading is a cool hobby. The problem is that it is super expensive and requires a great deal of space. It also requires a fair amount of technical knowledge.

A scale that fascinates me the most is HOn30 (HOn2½, HO9, or H0e) because the trains run on N-scale track while being HO scale. The nice thing about model railroading is that it is socially acceptable for older adults to do, given how expensive it is.